For a film capacitor used in SiC controller, the internal temperature distribution is studied by combining finite element thermal simulation analysis and bench test. The internal structure of film capacitor is designed, the structure layout of the film capacitor in the SiC controller is introduced, and the thermal simulation model of the film capacitor is established. The temperature distribution rule of the film capacitor under the rated working condition of the SiC controller is mainly studied. The film capacitor sample is made and thermocouples are embedded in it. The actual temperature of the film capacitor under the rated working condition is verified by bench test. Through the comparative analysis of the simulation and test results, the effectiveness of using finite element thermal simulation to study the film capacitor of SiC controller is proved. The research results can provide certain reference value for the efficient heat dissipation design of the film capacitor for SiC controller.