diff --git a/backend/packages/backend/src/services/proposal.service/whitelistOnePersonOneVote.js b/backend/packages/backend/src/services/proposal.service/whitelistOnePersonOneVote.js
new file mode 100644
index 00000000..3eeda9b2
--- /dev/null
+++ b/backend/packages/backend/src/services/proposal.service/whitelistOnePersonOneVote.js
@@ -0,0 +1,122 @@
+const { getProposalCollection, getVoteCollection } = require("../../mongo");
+const { HttpError } = require("../../exc");
+const { pinData } = require("./common");
+const { isSameAddress } = require("../../utils/address");
+
+async function checkWhitelistMember(networksConfig, address) {
+  if (
+    (networksConfig.whitelist || []).findIndex((item) =>
+      isSameAddress(item, address),
+    ) === -1
+  ) {
+    throw new HttpError(400, "Only members can vote on this proposal");
+  }
+}
+
+async function saveVote({
+  data,
+  address,
+  signature,
+  proposal,
+  voter,
+  voterNetwork,
+  choices,
+  remark,
+  now,
+  weights,
+  proposalCol,
+  proposalCid,
+}) {
+  const { cid, pinHash } = await pinData({
+    data,
+    address,
+    signature,
+  });
+
+  const voteCol = await getVoteCollection();
+
+  voteCol.updateOne(
+    {
+      proposal: proposal._id,
+      voter,
+      voterNetwork,
+    },
+    {
+      $set: {
+        choices,
+        remark,
+        data,
+        address,
+        signature,
+        updatedAt: now,
+        cid,
+        pinHash,
+        weights,
+        // Version 2: multiple network space support
+        // Version 3: multiple choices support
+        // Version 4: multi-assets network
+        version: "4",
+      },
+      $setOnInsert: {
+        createdAt: now,
+      },
+    },
+    { upsert: true },
+  );
+
+  await proposalCol.updateOne(
+    { cid: proposalCid },
+    {
+      $set: {
+        lastActivityAt: new Date(),
+      },
+    },
+  );
+}
+
+async function vote(
+  proposalCid,
+  choices,
+  remark,
+  data,
+  address,
+  voterNetwork,
+  signature,
+) {
+  const voter = address;
+
+  const proposalCol = await getProposalCollection();
+  const proposal = await proposalCol.findOne({ cid: proposalCid });
+  if (!proposal) {
+    throw new HttpError(400, "Proposal not found.");
+  }
+
+  await checkWhitelistMember(proposal.networksConfig, voter);
+
+  const now = new Date();
+
+  const weights = { onePersonOneVote: 1 };
+
+  await saveVote({
+    data,
+    address,
+    signature,
+    proposal,
+    voter,
+    voterNetwork,
+    choices,
+    remark,
+    now,
+    weights,
+    proposalCol,
+    proposalCid,
+  });
+
+  return {
+    success: true,
+  };
+}
+
+module.exports = {
+  vote,
+};