diff --git a/README.md b/README.md
index 1e27b00..7dc19d1 100644
--- a/README.md
+++ b/README.md
@@ -159,7 +159,7 @@ allprojects {
 ```
 ```groovy
 dependencies {
-    implementation 'com.github.zeshaoaaa:OkReflect:0.0.9'
+    implementation 'com.github.zeshaoaaa:OkReflect:0.1.0'
 }
 ```
 ### Maven
@@ -175,6 +175,6 @@ dependencies {
 	<dependency>
 	    <groupId>com.github.zeshaoaaa</groupId>
 	    <artifactId>OkReflect</artifactId>
-	    <version>0.0.9</version>
+	    <version>0.1.0</version>
 	</dependency>
 ```
diff --git a/README_CN.md b/README_CN.md
index 480c97f..d05c1de 100644
--- a/README_CN.md
+++ b/README_CN.md
@@ -162,7 +162,7 @@ allprojects {
 ```
 ```groovy
 dependencies {
-    implementation 'com.github.zeshaoaaa:OkReflect:0.0.9'
+    implementation 'com.github.zeshaoaaa:OkReflect:0.1.0'
 }
 ```
 ### Maven
@@ -178,6 +178,6 @@ dependencies {
 	<dependency>
 	    <groupId>com.github.zeshaoaaa</groupId>
 	    <artifactId>OkReflect</artifactId>
-	    <version>0.0.9</version>
+	    <version>0.1.0</version>
 	</dependency>
 ```
diff --git a/build.gradle b/build.gradle
index cf431de..dee9e89 100644
--- a/build.gradle
+++ b/build.gradle
@@ -11,7 +11,7 @@ plugins {
 apply plugin: 'maven'
 
 group 'com.github.zeshaoaaa'
-version '0.0.9'
+version '0.1.0'
 
 sourceCompatibility = 1.8
 
diff --git a/src/main/kotlin/okreflect/OkReflect.kt b/src/main/kotlin/okreflect/OkReflect.kt
index 2d74838..f9be94c 100644
--- a/src/main/kotlin/okreflect/OkReflect.kt
+++ b/src/main/kotlin/okreflect/OkReflect.kt
@@ -71,6 +71,11 @@ class OkReflect {
      */
     private var result: Any? = null
 
+    /**
+     * Whether call methods with outer instance or not.
+     */
+    private var withOuterInstance = false
+
     /**
      * @param className: The name of the class that you want to create.
      *
@@ -89,6 +94,17 @@ class OkReflect {
         this.clazz = clazz
     }
 
+    /**
+     * @param instance: The instance that you want to use for calling methods.
+     *
+     * Constructor of OkReflect.
+     */
+    constructor(instance: Any) {
+        withOuterInstance = true
+        this.instance = instance
+        this.clazz = instance.javaClass
+    }
+
     /**
      * Set the parameters of the constructor of the class that you want to create.
      */
@@ -370,16 +386,20 @@ class OkReflect {
      * and set or get the field that you want.
      */
     private fun <T> realGet(returnFlag: Int): T? {
-        val needInstance = returnFlag == RETURN_FLAG_INSTANCE || returnFlag == RETURN_FLAG_RESULT
-        if (needInstance) {
-            verifyClassInfo()
-            verifyConstructorArgs()
-        }
-        if (clazz == null) {
-            this.clazz = Class.forName(className!!)
-        }
-        if (createCalled) {
-            initInstance()
+        if (!withOuterInstance) {
+            val needInstance = returnFlag == RETURN_FLAG_INSTANCE || returnFlag == RETURN_FLAG_RESULT
+            if (needInstance) {
+                verifyClassInfo()
+                verifyConstructorArgs()
+            }
+            if (clazz == null) {
+                this.clazz = Class.forName(className!!)
+            }
+            if (createCalled) {
+                initInstance()
+                invokeMethods()
+            }
+        } else {
             invokeMethods()
         }
         setFields()
@@ -388,10 +408,10 @@ class OkReflect {
     }
 
     /**
-     * If there is no constructor parameters, there will throw an exception
+     * If there is no constructor parameters for the , there will throw an exception
      */
     private fun verifyConstructorArgs() {
-        if (constructorArgs == null) {
+        if (!withOuterInstance && constructorArgs == null) {
             throw NullPointerException(
                 "you have to call create() method, or else you will get nothing."
             )
@@ -402,7 +422,7 @@ class OkReflect {
      * If there is no class info, there will throw an exception
      */
     private fun verifyClassInfo() {
-        if (clazz == null && className == null && className!!.isEmpty()) {
+        if (!withOuterInstance && clazz == null && className == null && className!!.isEmpty()) {
             throw java.lang.NullPointerException(
                 "you must specify the className or class."
             )
@@ -489,6 +509,16 @@ class OkReflect {
             return OkReflect(clazz)
         }
 
+        /**
+         * @param instance: The instance that you want to use.
+         *
+         * Set the instance for methods that you want to call.
+         */
+        @JvmStatic
+        fun on(instance: Any): OkReflect {
+            return OkReflect(instance)
+        }
+
         /**
          * Change the accessibility of the methods and constructors.
          */
diff --git a/src/test/java/UseCaseTest.java b/src/test/java/UseCaseTest.java
index fc953ba..8d0469b 100644
--- a/src/test/java/UseCaseTest.java
+++ b/src/test/java/UseCaseTest.java
@@ -1,6 +1,7 @@
 import okreflect.OkReflect;
 import org.jetbrains.annotations.NotNull;
 import org.junit.Assert;
+import org.junit.Ignore;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
 
@@ -177,13 +178,6 @@ public void testSetFinalFieldOfInstance() {
         assert finalField.equals("changed");
     }
 
-    @Test
-    public void testSetFinalFieldOfClass() {
-        String finalField = OkReflect.on("TestClass")
-                .set("finalString", "changed")
-                .get("finalString");
-        assert finalField.equals("changed");
-    }
 
     @Test
     public void testGetClass() {
@@ -209,5 +203,32 @@ public void testSetStaticFinalFieldOfClass() {
         assert finalField.equals("changed");
     }
 
+    @Test
+    public void testCallMethodFromOuterInstance() {
+        TestClass testClass = new TestClass();
+        String name = OkReflect.on(testClass)
+                .call("getName")
+                .get();
+        assert name.equals("default");
+    }
+
+    @Test
+    public void testSetFieldFromOuterInstance() {
+        TestClass testClass = new TestClass();
+        String name = OkReflect.on(testClass)
+                .set("name", "Alex")
+                .get("name");
+        assert name.equals("Alex");
+    }
+
+    @Ignore
+    @Test
+    public void testSetFinalFieldOfClass() {
+        String finalField = OkReflect.on("TestClass")
+                .set("finalString", "changed")
+                .get("finalString");
+        assert finalField.equals("changed");
+    }
+
 
 }