Abstract: In order to study the variation law of the maximum explosion pressure and the maximum pressure rise rate of the premixed gas in the flameproof enclosure, three different flameproof enclosures were selected as the test samples, and the explosion was carried out by filling the premixed typical combustible gas in the flameproof enclosure. In the experiment, the relationship between maximum explosion pressure and its rise rate with the length-diameter ratio of the flameproof enclosure and the position of the ignition source was analyzed. In order to reveal the pressure piling phenomenon in the experiment, the mechanism was analyzed by numerical simulation. The results show that the maximum explosion pressure of the flameproof enclosure has a negative nonlinear relationship with the length-diameter ratio of the flameproof enclosure, the maximum explosion pressure is more affected by the surface area of the cavity, and the rate of increase of the maximum explosion pressure decreases with the increaseof the length-diameter ratio; the explosion-proof enclosure of the double-chamber communication structure is prone to pressure piling, and the ignition position in the pressure piling has a significant effect on the maximum explosion pressure and the maximum explosion pressure rise rate; the maximum pressure rise rate produced by hydrogen as a typical gas is significantly higher than that of ethylene.