Abstract: Polymer film capacitors are widely used in engineering fields due to the advantages of high power density, high safety and good insulation and so on. In recent years, with the increasing demand of high temperature energy storage of dielectric thin film capacitors in new energy transportation, clean energy grid connection, oil and gas exploitation, etc., the energy storage properties of dielectric film capacitors under extreme conditions such as high temperature and high electric field have attracted more and more attention, which has being a research hotspot in the field of electrical materials. In this paper, the research progress of high temperature energy storage of polymer-based composite dielectric films in recent years are summarized. Firstly, the key parameters that determine high temperature energy storage characteristics of dielectric materials are introduced, and the influences of high temperature and high electric field on these key parameters are analyzed. Secondly, the research status of the optimized of high-temperature energy storage properties of polymer-based films with different spatial levels are reviewed, and the adjusting methods for high-temperature energy storage properties are summarized from the aspects of molecular structure, micro structure and mesoscopic structure. Finally, a brief prospect for further improving the high temperature energy storage properties of polymer films is presented.