diff --git a/src/main/java/org/bdware/server/action/MasterWSAction.java b/src/main/java/org/bdware/server/action/MasterWSAction.java
index 60945c9..4fd73ec 100644
--- a/src/main/java/org/bdware/server/action/MasterWSAction.java
+++ b/src/main/java/org/bdware/server/action/MasterWSAction.java
@@ -26,10 +26,7 @@ import org.bdware.units.NetworkManager;
 import org.zz.gmhelper.SM2KeyPair;
 import org.zz.gmhelper.SM2Util;
 
-import java.util.Arrays;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
+import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.stream.Collectors;
 
@@ -139,7 +136,7 @@ public class MasterWSAction {
             }
         }
         */
-        List<String> nodeNames; // nodes' peerID
+        Set<String> nodeNames; // nodes' peerID
 //        if (contract.getType().equals(ContractExecType.SelfAdaptiveSharding)) {
 //            if (ContractManager.instance.nodeCenterConn.listNodes().length < 3) {
 //                rc.onResult(
@@ -160,16 +157,18 @@ public class MasterWSAction {
         nodeNames =
                 Arrays.stream(nodeNamesStr)
                         .filter(x -> null != x && !x.isEmpty())
-                        .collect(Collectors.toList());
+                        .collect(Collectors.toSet());
 //        }
+
+        SM2KeyPair keyPair = GlobalConf.instance.keyPair;
+        String masterNode = keyPair.getPublicKeyStr();
+        nodeNames.add(masterNode);
         int nodeSize = nodeNames.size();
 
         // 方式一向NodeCenter发，要求Slave节点主动连接到Master节点.
         Map<String, Object> requestConnect = new HashMap<>();
         requestConnect.put("action", "requestConnectToMaster");
         LOGGER.debug(multiPointContractInfo.masterNode);
-        SM2KeyPair keyPair = GlobalConf.instance.keyPair;
-        String masterNode = keyPair.getPublicKeyStr();
         requestConnect.put("master", masterNode); // 从哪个节点启动，哪个节点就是master
         requestConnect.put("members", nodeNames);
         if (contract.getType() == ContractExecType.Sharding) {
@@ -256,12 +255,12 @@ public class MasterWSAction {
         String startReq = JsonUtil.toJson(request);
         LOGGER.debug("start contract " + startReq);
 
-        for (int i = 0; i < nodeSize; ++i) {
-            String nodeID = nodeNames.get(i); // 根据i获得nodeID
+        int i = 0;
+        for (String nodeID : nodeNames) {
             // for (String nodeID : nodeNames) {
             // 设置字段
             if (multiPointContractInfo.type == ContractExecType.Sharding) {
-                contract.setShardingId(i);
+                contract.setShardingId(i++);
                 request.put("contractStr", JsonUtil.toJson(contract));
                 startReq = JsonUtil.toJson(request);
                 LOGGER.debug("start contract: " + startReq);
@@ -292,7 +291,7 @@ public class MasterWSAction {
         LOGGER.info("success!");
     }
 
-    private boolean waitForConnection(List<String> nodeNames) {
+    private boolean waitForConnection(Collection<String> nodeNames) {
         LOGGER.info("waitForAllNodes:" + JsonUtil.toJson(nodeNames));
         for (int i = 0; i < 5; i++) {
             boolean all = true;