Abstract: Xiagou Coal Mine 403 mining area uses “U” style ventilation to mine 301 working face, and there is a high proportion of gas flowing into the working face, which can cause gas accumulation at upper corner. For this problem, pressure balancing ventilation technology is proposed to control gas at upper corner, and this technology achieves a good effect through the practical application. But, analyzing the gas measured data of working face, the problem of pressure balancing ventilation “equilibrium point” was found. Through the establishment of ventilation network solution mode of 301 working face, the cause of "equilibrium point" is analyzed by numerical simulation and data analysis, and the results are close to the theory values.