Abstract: Aiming at the problems of the complex operation and many links of the braking mode of existing downhole carrying vehicles, the mechanical brake scheme of the electromechanical combined crank rocker mechanism and drum brake was proposed. In order to explore the interaction between brake temperature field and stress field in the braking process, the three-dimensional structure model of drum brake is established by CATIA, and then, the coupling process of transient heat field and stress field is simulated and analyzed based on ABAQUS. Finally, the temperature and stress distribution of the brake drum, brake shoe and friction plate are obtained, and the equivalent stress concentration area of the brake at the end of braking is determined.