Abstract: Film capacitors are important in high-tech fields such as power transmission and transformation systems, electric vehicles, and pulse power systems. Currently, the performance of capacitors is limited by the biaxially oriented polypropylene film, which leads to low energy storage density, poor temperature resistance, few charge and discharge cycles, and short lifespan of capacitors. This seriously affects the further improvement of the performance of metallized film capacitors and cannot meet the demands of high-energy-density metallized film capacitors in many fields. However, the key issues, including limited improvement in the comprehensive performance of dielectric materials for high-energy-density capacitors, and the difficulty in the industrial production of high-energy-density dielectric polymer materials from the small-sized samples produced in a laboratory, make it difficult to verify the comprehensive performance of metalized film capacitors. Therefore, several important perspectives and advice, including materials composite technology, materials chemical modification, and coating layers modification as well as the energy storage performance enhancement of dielectric films and high-energy-density capacitors design, are proposed in this article to guide the future research direction and promote the development of advanced dielectric materials for high-energy-density film capacitor application in China.