Abstract: The structure and working principle of mechanical flameproof device in underground coal mine were introduced. By using simulation test roadway and XC-G0110 explosion comprehensive test system, the explosion pressure of gas and coal dust and flame propagation were investigated under the condition of no flameproof device, one flameproof device and two flameproof devices respectively, the comparison results of flameproof effect under these three conditions were obtained. The test shows that when two sets of flameproof devices are installed,the explosion flame does not exceed 13 m behind the flameproof device,the peak attenuation of explosion pressure reaches 73%, which can effectively isolate the propagation of gas and coal dust explosion flame. The reasons for the difference in the flameproof effect are analyzed, it can provide guidance for the correct installation and use of the device in underground coal mine.