Based on the analysis of meshing equations of bevel gears, the method of setting solid model was used by bottom-up and 8-nodes element of hexahedron, and its finite element 3-D model of three gear teeth was established. According to the theory of heat conduction, the bulk static temperature field of the model was obtained. Then by coupling of the two physical fields of thermal and structure, its thermal stress and thermal deformation were simulated and analyzed. The analysis results show these important conclusions as follow. Firstly, while many teeth of bevel gear are meshing, the bulk static temperature of meshing center of one tooth is highest. Secondly, the place of greatest thermal stress does not locate at its meshing center, but its tooth root. Thirdly, the place of the greatest thermal deformation is the tooth top.