diff --git a/README.md b/README.md
index 54055f7..095339c 100644
--- a/README.md
+++ b/README.md
@@ -56,3 +56,72 @@
 
 * cb`func`: 应用消息回调，例如：` def callback(topic:str, msg:bytes): print(str(msg,'utf-8')`
 * rrpc_cb`func`: 应用RRPC消息回调，例如：` def callback(topic:str, msg:bytes): print(str(msg,'utf-8')`
+
+## Demo
+```
+import json
+import logging
+import time
+
+from iotedgeapplicationlinksdk import getLogger
+from iotedgeapplicationlinksdk.client import get_application_config, get_application_name, get_gateway_product_sn, get_gateway_device_sn, publish, register_callback
+
+# 配置log
+log = getLogger()
+log.setLevel(logging.DEBUG)
+
+# 主函数
+if __name__ == "__main__":
+    try:
+        # 获取应用配置信息
+        appConfig = get_application_config()
+        log.info('app config:{}'.format(appConfig))
+
+        # 从应用配置获取设备数据上报周期
+        uploadPeriod = 5
+        if "period" in appConfig.keys() and isinstance(appConfig['period'], int):
+            uploadPeriod = int(appConfig['period'])
+
+        appName = get_application_name()
+        productSN = get_gateway_product_sn()
+        deviceSN = get_gateway_device_sn()
+        log.info('app info:{}, {}, {}'.format(appName, productSN, deviceSN))
+
+        # 设置应用上报topic
+        topic = '/{}/{}/upload'.format(productSN, deviceSN)
+
+        # 设置应用消息回调
+        def callback(topic: str, payload: bytes):
+            log.info("recv message from {} : {}".format(topic, str(payload)))
+
+        # 设置应用RRPC消息回调
+        def rrpc_callback(topic: str, payload: bytes):
+            log.info("recv rrpc message from {} : {}".format(
+                topic, str(payload)))
+
+        register_callback(callback, rrpc_callback)
+        i = 0
+        # 周期上报消息
+        while True:
+            relayStatus = ("on", "off")[i % 2 == 0]
+            payload = {
+                "timestamp": time.time(),
+                'RelayStatus': relayStatus
+            }
+
+            byts = json.dumps(payload).encode('utf-8')
+
+            publish(topic, byts)
+
+            log.info("upload {} : {}".format(topic, str(byts)))
+
+            time.sleep(uploadPeriod)
+            i = i+1
+            if (i > 1000):
+                i = 1
+
+    except Exception as e:
+        log.error('load app config error: {}'.format(str(e)))
+        exit(1)
+
+```
\ No newline at end of file
diff --git a/examples/demo/index.py b/examples/demo/index.py
index 0b6d755..32b74dc 100644
--- a/examples/demo/index.py
+++ b/examples/demo/index.py
@@ -12,11 +12,11 @@ log.setLevel(logging.DEBUG)
 # 主函数
 if __name__ == "__main__":
     try:
-        # 获取驱动及子设备配置信息
+        # 获取应用配置信息
         appConfig = get_application_config()
         log.info('app config:{}'.format(appConfig))
 
-        # 从驱动配置获取设备数据上报周期
+        # 从应用配置获取设备数据上报周期
         uploadPeriod = 5
         if "period" in appConfig.keys() and isinstance(appConfig['period'], int):
             uploadPeriod = int(appConfig['period'])
@@ -26,19 +26,21 @@ if __name__ == "__main__":
         deviceSN = get_gateway_device_sn()
         log.info('app info:{}, {}, {}'.format(appName, productSN, deviceSN))
 
-        # 判断是否绑定子设备
+        # 设置应用上报topic
         topic = '/{}/{}/upload'.format(productSN, deviceSN)
 
+        # 设置应用消息回调
         def callback(topic: str, payload: bytes):
             log.info("recv message from {} : {}".format(topic, str(payload)))
 
+        # 设置应用RRPC消息回调
         def rrpc_callback(topic: str, payload: bytes):
             log.info("recv rrpc message from {} : {}".format(
                 topic, str(payload)))
 
         register_callback(callback, rrpc_callback)
-
         i = 0
+        # 周期上报消息
         while True:
             relayStatus = ("on", "off")[i % 2 == 0]
             payload = {
@@ -54,6 +56,8 @@ if __name__ == "__main__":
 
             time.sleep(uploadPeriod)
             i = i+1
+            if (i > 1000):
+                i = 1
 
     except Exception as e:
         log.error('load app config error: {}'.format(str(e)))
diff --git a/iotedgeapplicationlinksdk/client.py b/iotedgeapplicationlinksdk/client.py
index 0c25078..e06c341 100644
--- a/iotedgeapplicationlinksdk/client.py
+++ b/iotedgeapplicationlinksdk/client.py
@@ -80,8 +80,11 @@ class _natsClientSub(object):
                 data = base64.b64decode(js['payload'])
                 if isinstance(topic, str) and topic.startswith("/$system/") and topic.count('/rrpc/request/') > 0:
                     topic = topic.replace("/request/", "/response/", 1)
-                    _msg_rrpc_cb(topic, data)
-                else:
+                    if _msg_rrpc_cb:
+                        _msg_rrpc_cb(topic, data)
+                        return
+
+                if _msg_cb:
                     _msg_cb(topic, data)
             except Exception as e:
                 _logger.error('handle msg error {}'.format(str(e)))