Abstract: For functions of communication subsystem of monitoring system of gas in mine of a mining group,the paper put forward an implementation scheme. It described composition structure and implementation flow of function of the communication subsystem, analyzed and established communication protocol. The communication subsystem was designed by VB,adopted duplex communication mode, data format of data frame, and timed detecting mode, which enhanced capability of whole communication system, provided a high- efficiency and credible communication platform for monitoring system of gas in mine.