Abstract: In view of problems of slow speed of gas distribution, big volume of system of traditional gas distribution methods applied in flameproof test devices, an automatic gas distribution system based on mass flow method was designed. The system uses mass flow controller to control flow of several different gases accurately, and the output gases are mixed uniformly by mixed equipment. Volume fractions of the mixed gases are monitored real-timely by oxygen analyzer and hydrogen analyzer. The test result shows that the gas distribution system has fast speed of gas distribution and simple structure, and precision of the volume fractions of the gases distributed by the system can meet requirements of GB 3836.2-2010.