In order to further grasp the law of gas transportation and accumulation in the comprehensive mining working face, this paper combined with the actual situation of 18402 working face of Tunlan Mine, analyzed the main gas sources and basic transportation mode of the working face, and established the gas transportation model of the working face by using FLUENT software, the numerical simulation results show that the gas concentration in the working face gradually increases from the inlet to the return air alley, and in the return air upper corner In order to solve the problem of gas accumulation in the upper corner of the return wind, 18402 working face adopts management measures such as burying pipe extraction in the extraction area, hanging wind barriers, strengthening monitoring and management, etc., with obvious practical effects.