diff --git a/broker/src/test/java/org/apache/rocketmq/broker/processor/MQTTProcessorTest.java b/broker/src/test/java/org/apache/rocketmq/broker/processor/MQTTProcessorTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..d956a8850a103d4353e280ff4081ea8a62b40854
--- /dev/null
+++ b/broker/src/test/java/org/apache/rocketmq/broker/processor/MQTTProcessorTest.java
@@ -0,0 +1,186 @@
+package org.apache.rocketmq.broker.processor;
+
+import com.google.gson.Gson;
+import com.google.gson.reflect.TypeToken;
+import org.apache.rocketmq.broker.BrokerController;
+import org.apache.rocketmq.common.BrokerConfig;
+import org.apache.rocketmq.common.client.ClientRole;
+import org.apache.rocketmq.common.client.Subscription;
+import org.apache.rocketmq.common.protocol.RequestCode;
+import org.apache.rocketmq.common.protocol.header.mqtt.*;
+import org.apache.rocketmq.common.protocol.heartbeat.MqttSubscriptionData;
+import org.apache.rocketmq.mqtt.client.MQTTSession;
+import org.apache.rocketmq.mqtt.constant.MqttConstant;
+import org.apache.rocketmq.remoting.ClientConfig;
+import org.apache.rocketmq.remoting.RemotingChannel;
+import org.apache.rocketmq.remoting.ServerConfig;
+import org.apache.rocketmq.remoting.exception.RemotingCommandException;
+import org.apache.rocketmq.remoting.netty.CodecHelper;
+import org.apache.rocketmq.remoting.protocol.RemotingCommand;
+import org.apache.rocketmq.store.DefaultMQTTInfoStore;
+import org.apache.rocketmq.store.MQTTInfoStore;
+import org.apache.rocketmq.store.config.MessageStoreConfig;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.Spy;
+import org.mockito.junit.MockitoJUnitRunner;
+
+import java.net.InetSocketAddress;
+import java.util.HashSet;
+import java.util.Set;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.when;
+
+
+@RunWith(MockitoJUnitRunner.class)
+public class MQTTProcessorTest {
+
+
+    private MQTTProcessor requestProcessor;
+    @Spy
+    private BrokerController brokerController = new BrokerController(new BrokerConfig(), new ServerConfig(), new ClientConfig(), new MessageStoreConfig());
+
+    private static MQTTInfoStore mqttInfoStore;
+    @Mock
+    private RemotingChannel remotingChannel;
+
+    private MQTTSession mqttSession;
+    private static final Gson GSON = new Gson();
+    private static final String CLIENT_ID = "testClient";
+    private static final String ROOT_TOPIC = "rootTopic";
+
+
+    private Subscription subscription;
+
+    static {
+
+        try {
+            mqttInfoStore = new DefaultMQTTInfoStore();
+            mqttInfoStore.load();
+            mqttInfoStore.start();
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+
+
+    @Before
+    public void init() throws Exception {
+
+        when(brokerController.getMqttInfoStore()).thenReturn(mqttInfoStore);
+        when(remotingChannel.remoteAddress()).thenReturn(new InetSocketAddress(1024));
+        requestProcessor = new MQTTProcessor(brokerController);
+        this.mqttSession = new MQTTSession(CLIENT_ID, ClientRole.IOTCLIENT, new HashSet<String>() {
+            {
+                add("IOT_GROUP");
+            }
+        }, true, true, null, System.currentTimeMillis(), null);
+
+
+        subscription = new Subscription();
+        subscription.setCleanSession(true);
+        subscription.getSubscriptionTable().put("topic/a", new MqttSubscriptionData(1, "client1", "topic/a"));
+        subscription.getSubscriptionTable().put("topic/+", new MqttSubscriptionData(1, "client1", "topic/+"));
+        subscription.setLastUpdateTimestamp(System.currentTimeMillis());
+    }
+
+    @Test
+    public void testReqProc_IsClient2SubscriptionPersisted() throws RemotingCommandException {
+        mqttInfoStore.putData(CLIENT_ID + MqttConstant.PERSIST_CLIENT_SUFFIX, GSON.toJson(mqttSession));
+        final RemotingCommand request = createIsClient2SubscriptionPersistedRequestHeader(RequestCode.MQTT_IS_CLIENT2SUBSCRIPTION_PERSISTED);
+        RemotingCommand responseToReturn = requestProcessor.processRequest(remotingChannel, request);
+        if (responseToReturn != null) {
+            IsClient2SubscriptionPersistedResponseHeader mqttHeader = (IsClient2SubscriptionPersistedResponseHeader) responseToReturn.readCustomHeader();
+            assertThat(mqttHeader).isNotNull();
+            assertThat(mqttHeader.isPersisted()).isEqualTo(true);
+        }
+    }
+
+
+    private RemotingCommand createIsClient2SubscriptionPersistedRequestHeader(int requestCode) {
+        IsClient2SubscriptionPersistedRequestHeader requestHeader = new IsClient2SubscriptionPersistedRequestHeader();
+        requestHeader.setClientId(CLIENT_ID);
+        requestHeader.setCleanSession(false);
+        RemotingCommand request = RemotingCommand.createRequestCommand(requestCode, requestHeader);
+        request.setBody(new byte[]{'a'});
+        CodecHelper.makeCustomHeaderToNet(request);
+        return request;
+    }
+
+
+
+
+
+    @Test
+    public void testReqProc_AddorUpdateRootTopic2Clients() throws RemotingCommandException {
+        final RemotingCommand request = createAddorUpdateRootTopic2Clients(RequestCode.MQTT_ADD_OR_UPDATE_ROOTTOPIC2CLIENTS);
+        RemotingCommand responseToReturn = requestProcessor.processRequest(remotingChannel, request);
+        if (responseToReturn != null) {
+            AddOrUpdateRootTopic2ClientsResponseHeader mqttHeader = (AddOrUpdateRootTopic2ClientsResponseHeader) responseToReturn.readCustomHeader();
+            assertThat(mqttHeader).isNotNull();
+            assertThat(mqttHeader.isOperationSuccess()).isEqualTo(true);
+        }
+        String value = mqttInfoStore.getValue(ROOT_TOPIC);
+        Set<String> clientsId;
+        if (value != null) {
+            clientsId = GSON.fromJson(value, new TypeToken<Set<String>>() {
+            }.getType());
+        } else {
+            clientsId = new HashSet<>();
+        }
+        assertThat(clientsId).contains(CLIENT_ID);
+    }
+
+
+    private RemotingCommand createAddorUpdateRootTopic2Clients(int requestCode) {
+        AddOrUpdateRootTopic2ClientsRequestHeader requestHeader = new AddOrUpdateRootTopic2ClientsRequestHeader();
+        requestHeader.setRootTopic(ROOT_TOPIC);
+        requestHeader.setClientId(CLIENT_ID);
+
+        RemotingCommand request = RemotingCommand.createRequestCommand(requestCode, requestHeader);
+        request.setBody(new byte[]
+                {
+                        'a'
+                });
+        CodecHelper.makeCustomHeaderToNet(request);
+        return request;
+    }
+
+
+    @Test
+    public void testReqProc_GetSubscriptionByClientId() throws RemotingCommandException {
+        String subscriptionStr = GSON.toJson(subscription);
+        this.mqttInfoStore.putData(CLIENT_ID + MqttConstant.PERSIST_SUBSCRIPTION_SUFFIX, subscriptionStr);
+
+        final RemotingCommand request = createGetSubscriptionByClientId(RequestCode.MQTT_GET_SUBSCRIPTION_BY_CLIENT_ID);
+        RemotingCommand responseToReturn = requestProcessor.processRequest(remotingChannel, request);
+        if (responseToReturn != null) {
+            GetSubscriptionByClientIdResponseHeader mqttHeader = (GetSubscriptionByClientIdResponseHeader) responseToReturn.readCustomHeader();
+            assertThat(mqttHeader).isNotNull();
+            assertThat(mqttHeader.getSubscription()).isNotNull();
+
+            assertThat(subscription.getLastUpdateTimestamp()).isEqualTo(mqttHeader.getSubscription().getLastUpdateTimestamp());
+        }
+
+
+    }
+
+
+    private RemotingCommand createGetSubscriptionByClientId(int requestCode) {
+        GetSubscriptionByClientIdRequestHeader requestHeader = new GetSubscriptionByClientIdRequestHeader();
+        requestHeader.setClientId(CLIENT_ID);
+
+        RemotingCommand request = RemotingCommand.createRequestCommand(requestCode, requestHeader);
+        request.setBody(new byte[]
+                {
+                        'a'
+                });
+        CodecHelper.makeCustomHeaderToNet(request);
+        return request;
+    }
+
+
+}