Abstract: The method of connection establishment method in data transmission between micro-services in cloud ensures reducing connection complexity between client instances and server instances, increasing the number of connections which helps increase data transmission performance. Besides, the method helps ensure load balancing when server instances change or in time of failure. The proposed method includes the following steps: step 1: data preparation; Step 2: build connection data table; Step 3: select the appropriate connection when receiving a request to send data from the client; step 4: periodically queries the independent service management, updating the current state of the server instances.