Abstract: Metallized film capacitor(MFC) with high energy density and good reliability is widely used in the field of high voltage and large capacity power electronic system. In the working state, repeated charging and discharging process will make the internal temperature of the capacitor rise, too high internal temperature will lead to the reliability of the capacitor and affect the system reliability. A three-dimensional electric field model of metallized film capacitor is established to obtain its power loss. The thermal model of metallized film capacitor is solved by using finite element software, and the temperature rise of the capacitor is simulated under the actual working condition. Finally, the charging and discharging experiment platform of metalized film capacitor is built, and the temperature distribution experiment is conducted to verify the accuracy of the established finite element model. The results show that the electrothermal model of metallized film capacitor can accurately describe the temperature rise under normal working conditions. The work will provide reference for capacitor life prediction and reliability analysis of power electronic system.