In order to solve the problem that the test resistance box could safely go down the well, a mine resistance box explosion-proof shell was designed. According to the functional requirements of the mine test resistance box, the corresponding wiring port was designed on the explosion-proof shell of the resistance box. In order to meet the requirements of explosion-proof strength, the explosion-proof shell was strengthened by ribs. In order to meet the safety clearance requirements of the flameproof surface, the steel plate of the contact surface was designed as a ' back ' frame, which ensured the flatness of the contact surface. Based on the three-dimensional modeling of the explosion-proof enclosure of the resistance box, the finite element static analysis was carried out according to the actual stress situation. According to the results of calculation and analysis, the weak dangerous parts of the explosion-proof shell were determined. According to the principle of optimization design, the structure of the bottom rib of the explosion-proof shell was optimized. The optimized structure was verified by finite element analysis and met the design requirements. The calculation data and design method of the explosion-proof enclosure designed in this paper provided a reference for the subsequent development of explosion-proof enclosures of other electrical appliances.