Abstract: Taking the secondary sub node system of industrial Internet as the platform and the coal mine monitoring system as the access object, this paper analyzes the structure of the industrial Internet system and the key technologies required for the monitoring system to access the industrial Internet, and designs and develops an access gateway. The gateway is applied to the connecting end of the switch and industrial Internet in the monitoring system. The data sent by the monitoring sub-station of the switch is analyzed and processed, then packaged in JSON format, and passed into the industrial Internet cloud software through MQTT protocol. The practical application shows that the scheme has reasonable architecture design, good stability and superior performance, and provides a feasible scheme for monitoring system to access industrial Internet.