diff --git a/python/ppml/src/bigdl/ppml/fl/nn/fl_client.py b/python/ppml/src/bigdl/ppml/fl/nn/fl_client.py
index 5061260c5ca..24ffd387d2f 100644
--- a/python/ppml/src/bigdl/ppml/fl/nn/fl_client.py
+++ b/python/ppml/src/bigdl/ppml/fl/nn/fl_client.py
@@ -18,13 +18,11 @@
 import logging
 import pickle
 import grpc
-from numpy import ndarray
 from bigdl.ppml.fl.nn.generated.nn_service_pb2 import TrainRequest, PredictRequest, UploadMetaRequest
 from bigdl.ppml.fl.nn.generated.nn_service_pb2_grpc import *
 from bigdl.ppml.fl.nn.utils import ndarray_map_to_tensor_map
 import yaml
 import threading
-from torch.utils.data import DataLoader
 from bigdl.dllib.utils.log4Error import invalidInputError
 
 from bigdl.ppml.fl.nn.utils import ClassAndArgsWrapper
@@ -32,6 +30,29 @@
 class FLClient(object):
     channel = None
     _lock = threading.Lock()
+    client_id = None
+    target = "localhost:8980"
+    secure = False
+    creds = None
+
+    @staticmethod
+    def set_client_id(client_id):
+        FLClient.client_id = client_id
+    
+    @staticmethod
+    def set_target(target):
+        FLClient.target = target
+
+    @staticmethod
+    def ensure_initialized():
+        with FLClient._lock:
+            if FLClient.channel == None:
+                if FLClient.secure:
+                    FLClient.channel = grpc.secure_channel(FLClient.target, FLClient.creds)
+                else:
+                    FLClient.channel = grpc.insecure_channel(FLClient.target)
+    
+
     def __init__(self, client_id, aggregator, target="localhost:8980") -> None:
         self.secure = False
         self.load_config()
@@ -91,3 +112,4 @@ def load_config(self):
             logging.warn('Loading config failed, using default config ')
         except Exception as e:
             logging.warn('Failed to find config file "ppml-conf.yaml", using default config')
+
diff --git a/python/ppml/src/bigdl/ppml/fl/nn/fl_context.py b/python/ppml/src/bigdl/ppml/fl/nn/fl_context.py
new file mode 100644
index 00000000000..815d297cb4b
--- /dev/null
+++ b/python/ppml/src/bigdl/ppml/fl/nn/fl_context.py
@@ -0,0 +1,22 @@
+#
+# Copyright 2016 The BigDL Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+from ..nn.fl_client import FLClient
+
+def init_fl_context(client_id, target="localhost:8980"):
+    FLClient.set_client_id(client_id)
+    FLClient.set_target(target)
+    FLClient.ensure_initialized()
diff --git a/python/ppml/src/bigdl/ppml/fl/nn/fl_server.py b/python/ppml/src/bigdl/ppml/fl/nn/fl_server.py
index 0dee411e31b..fa9517ab08c 100644
--- a/python/ppml/src/bigdl/ppml/fl/nn/fl_server.py
+++ b/python/ppml/src/bigdl/ppml/fl/nn/fl_server.py
@@ -17,10 +17,14 @@
 from concurrent import futures
 import grpc
 from bigdl.ppml.fl import *
-from bigdl.ppml.fl.nn.generated.nn_service_pb2_grpc import *
+
 from bigdl.ppml.fl.nn.nn_service import NNServiceImpl
 import yaml
-import logging
+
+from ..psi.psi_service import PSIServiceImpl
+from .generated.nn_service_pb2_grpc import *
+from .generated.psi_service_pb2_grpc import *
+
 
 
 class FLServer(object):
@@ -38,9 +42,8 @@ def set_port(self, port):
         self.port = port
         
     def build(self):
-        add_NNServiceServicer_to_server(
-            NNServiceImpl(conf=self.conf),            
-            self.server)
+        add_NNServiceServicer_to_server(NNServiceImpl(conf=self.conf), self.server)
+        add_PSIServiceServicer_to_server(PSIServiceImpl(conf=self.conf), self.server)
         if self.secure:
             self.server.add_secure_port(f'[::]:{self.port}', self.server_credentials)
         else:
diff --git a/python/ppml/test/bigdl/ppml/fl/algorithms/__init__.py b/python/ppml/src/bigdl/ppml/fl/psi/__init__.py
similarity index 100%
rename from python/ppml/test/bigdl/ppml/fl/algorithms/__init__.py
rename to python/ppml/src/bigdl/ppml/fl/psi/__init__.py
diff --git a/python/ppml/src/bigdl/ppml/fl/psi/psi.py b/python/ppml/src/bigdl/ppml/fl/psi/psi.py
new file mode 100644
index 00000000000..4095ea9d8d5
--- /dev/null
+++ b/python/ppml/src/bigdl/ppml/fl/psi/psi.py
@@ -0,0 +1,49 @@
+#
+# Copyright 2016 The BigDL Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+import logging
+
+from bigdl.dllib.utils.log4Error import invalidOperationError
+from ..nn.fl_client import FLClient
+from bigdl.ppml.fl.nn.generated.psi_service_pb2_grpc import *
+from ..nn.generated.psi_service_pb2 import DownloadIntersectionRequest, SaltRequest, UploadSetRequest
+
+class PSI(object):
+    def __init__(self) -> None:
+        self.stub = PSIServiceStub(FLClient.channel)
+    
+    def get_salt(self, secure_code=""):
+        return self.stub.getSalt(SaltRequest(secure_code=secure_code)).salt_reply
+    
+    def upload_set(self, ids, salt=""):
+        # TODO: add hashing
+        return self.stub.uploadSet(
+            UploadSetRequest(client_id=FLClient.client_id, hashedID=ids))
+
+    def download_intersection(self, max_try=100, retry=3):
+        for i in range(max_try):
+            intersection = self.stub.downloadIntersection(
+                DownloadIntersectionRequest()).intersection
+            if intersection is not None:
+                intersection = list(intersection)
+                logging.info(f"Intersection completed, size {len(intersection)}")
+                return intersection
+        invalidOperationError(False, "Max retry reached, could not get intersection, exiting.")
+
+    def get_intersection(self, ids, secure_code="", max_try=100, retry=3):
+        salt = self.stub.getSalt(SaltRequest(secure_code=secure_code)).salt_reply
+        self.upload_set(ids, salt)
+        return self.download_intersection(max_try, retry)
diff --git a/python/ppml/src/bigdl/ppml/fl/psi/psi_intersection.py b/python/ppml/src/bigdl/ppml/fl/psi/psi_intersection.py
new file mode 100644
index 00000000000..064559840cb
--- /dev/null
+++ b/python/ppml/src/bigdl/ppml/fl/psi/psi_intersection.py
@@ -0,0 +1,52 @@
+#
+# Copyright 2016 The BigDL Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+
+import logging
+import threading
+
+from bigdl.ppml.utils.log4Error import invalidOperationError
+
+
+class PsiIntersection(object):
+    def __init__(self, max_collection=1) -> None:
+        self.intersection = []
+        self._thread_intersection = []
+
+        self.max_collection = max_collection
+        self.condition = threading.Condition()
+        self._lock = threading.Lock()
+
+        self.collection = []
+        
+    def find_intersection(self, a, b):
+        return list(set(a) & set(b))
+
+    def add_collection(self, collection):
+        with self._lock:
+            invalidOperationError(len(self.collection) < self.max_collection,
+                f"PSI collection is full, got: {len(self.collection)}/{self.max_collection}")
+            self.collection.append(collection)
+            if len(self.collection) == self.max_collection:
+                current_intersection = self.collection[0]
+                for i in range(1, len(self.collection)):
+                    current_intersection = \
+                        self.find_intersection(current_intersection, self.collection[i])
+                self.intersection = current_intersection
+
+    def get_intersection(self):
+        with self._lock:
+            return self.intersection
\ No newline at end of file
diff --git a/python/ppml/src/bigdl/ppml/fl/psi/psi_service.py b/python/ppml/src/bigdl/ppml/fl/psi/psi_service.py
new file mode 100644
index 00000000000..958cdb36433
--- /dev/null
+++ b/python/ppml/src/bigdl/ppml/fl/psi/psi_service.py
@@ -0,0 +1,60 @@
+#
+# Copyright 2016 The BigDL Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+import logging
+from random import randint
+from uuid import uuid4
+from bigdl.ppml.fl.psi.psi_intersection import PsiIntersection
+from bigdl.ppml.fl.nn.generated.psi_service_pb2_grpc import *
+from bigdl.ppml.fl.nn.generated.psi_service_pb2 import *
+
+
+
+class PSIServiceImpl(PSIServiceServicer):
+    def __init__(self, conf) -> None:
+        self.client_salt = None
+        self.client_secret = None
+        self.client_shuffle_seed = 0
+        # self.psi_collections = {}
+        self.psi_intersection = PsiIntersection(conf['clientNum'])
+
+    def getSalt(self, request, context):
+        if self.client_salt is not None:
+            salt = self.client_salt
+        else:
+            salt = str(uuid4())
+            self.client_salt = salt
+        
+        if self.client_secret is None:
+            self.client_secret = request.secure_code
+        elif self.client_secret != request.secure_code:
+            salt = ""
+
+        if self.client_shuffle_seed == 0:
+            self.client_shuffle_seed = randint(0, 100)
+        return SaltReply(salt_reply=salt)
+
+    def uploadSet(self, request, context):
+        client_id = request.client_id
+        ids = request.hashedID
+        self.psi_intersection.add_collection(ids)
+        logging.info(f"{len(self.psi_intersection.collection)}-th collection added")
+        return UploadSetResponse(status=1)
+        
+
+    def downloadIntersection(self, request, context):
+        intersection = self.psi_intersection.get_intersection()
+        return DownloadIntersectionResponse(intersection=intersection)
diff --git a/python/ppml/src/bigdl/ppml/fl/psi/utils.py b/python/ppml/src/bigdl/ppml/fl/psi/utils.py
new file mode 100644
index 00000000000..3f987f434ad
--- /dev/null
+++ b/python/ppml/src/bigdl/ppml/fl/psi/utils.py
@@ -0,0 +1,17 @@
+#
+# Copyright 2016 The BigDL Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+# TODO: add security utils here
diff --git a/python/ppml/test/bigdl/ppml/fl/psi/__init__.py b/python/ppml/test/bigdl/ppml/fl/psi/__init__.py
new file mode 100644
index 00000000000..2151a805423
--- /dev/null
+++ b/python/ppml/test/bigdl/ppml/fl/psi/__init__.py
@@ -0,0 +1,15 @@
+#
+# Copyright 2016 The BigDL Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
diff --git a/python/ppml/test/bigdl/ppml/fl/psi/test_psi.py b/python/ppml/test/bigdl/ppml/fl/psi/test_psi.py
new file mode 100644
index 00000000000..d31cce4eb7d
--- /dev/null
+++ b/python/ppml/test/bigdl/ppml/fl/psi/test_psi.py
@@ -0,0 +1,53 @@
+#
+# Copyright 2016 The BigDL Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+import unittest
+
+
+from bigdl.ppml.fl.psi.psi import PSI
+from bigdl.ppml.fl.nn.fl_server import FLServer
+from bigdl.ppml.fl.nn.fl_context import init_fl_context
+from bigdl.ppml.fl.utils import FLTest
+
+class TestPSI(FLTest):
+    def setUp(self) -> None:
+        self.fl_server = FLServer(1)
+        self.fl_server.set_port(self.port)
+        self.fl_server.build()
+        self.fl_server.start()
+
+    def tearDown(self) -> None:
+        self.fl_server.stop()
+   
+        
+    def test_psi_get_salt(self):        
+        init_fl_context("1", self.target)
+        psi = PSI()
+        salt = psi.get_salt()
+        assert (isinstance(salt, str))
+
+    def test_psi_pipeline(self):
+        init_fl_context("1", self.target)
+        psi = PSI()
+        salt = psi.get_salt()
+        key = ["k1", "k2"]
+        psi.upload_set(key, salt)
+        intersection = psi.download_intersection()
+        assert (isinstance(intersection, list))
+        self.assertEqual(len(intersection), 2)
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/python/ppml/test/bigdl/ppml/fl/py4j/__init__.py b/python/ppml/test/bigdl/ppml/fl/py4j/__init__.py
new file mode 100644
index 00000000000..2151a805423
--- /dev/null
+++ b/python/ppml/test/bigdl/ppml/fl/py4j/__init__.py
@@ -0,0 +1,15 @@
+#
+# Copyright 2016 The BigDL Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
diff --git a/python/ppml/test/bigdl/ppml/fl/algorithms/test_fgboost_regression.py b/python/ppml/test/bigdl/ppml/fl/py4j/test_fgboost_regression.py
similarity index 100%
rename from python/ppml/test/bigdl/ppml/fl/algorithms/test_fgboost_regression.py
rename to python/ppml/test/bigdl/ppml/fl/py4j/test_fgboost_regression.py
diff --git a/python/ppml/test/bigdl/ppml/fl/algorithms/test_psi.py b/python/ppml/test/bigdl/ppml/fl/py4j/test_psi.py
similarity index 100%
rename from python/ppml/test/bigdl/ppml/fl/algorithms/test_psi.py
rename to python/ppml/test/bigdl/ppml/fl/py4j/test_psi.py