Abstract: In view of the problems of untimely opening and pressure relief of the traditional explosion-proof door and the low degree of automatic operation of the latch device, from the perspective of mechanics, the stress of the explosion-proof door under the two states of normal operation and reverse air operation of the fan is analyzed in detail. The application of the new electromagnetic latch technology to the explosion-proof door pressure relief and backdraft process was studied on the basis of the traditional latch, the required suction force of the new electromagnetic latch under different operating conditions of the fan was calculated and the design of the automatic explosion-proof door pressure relief was further proposed based on the electromagnetic latch technology. The results show that the explosion-proof door can be opened only when the explosion power is large, and there may be air leakage in the process of reverse wind. In order to prevent the above situations, in the proposed automatic pressure relief design of the explosion-proof door, the counterweight of the explosion-proof door is increased to the natural state, the explosion-proof door is pulled down, and the new electromagnetic latch is used to provide sufficient suction to meet the requirements of pressure relief and anti wind work of the explosion-proof door. The calculation shows that when the counterweightis 114 484 N to ensure the balance state of the explosion-proof door, the electromagnetic latch provides at least 166 169 N suction to ensure the smooth operation of the explosion-proof door in different working states of the fan. In addition, using the new electromagnetic latch and high-performance sensor technology, under the condition that the counterweight of the explosion-proof door is greater than the combined force of the gravity, positive（ｎｅｇａｔｉｖｅ） pressure and friction of the explosion-proof door cover, the rapid pressure relief under any explosion power can be realized when the distance between the explosion position and the explosion-proof door is greater than the distance that the explosion shock wave has propagated when the latch is powered off. Through theoretical calculation, it is concluded that the safe distance between the explosion position and the explosion-proof door in the automatic pressure relief design of the explosion-proof door is about 326 m.