Abstract: Thin film capacitors have important applications in the fields of electrical engineering and electronic devices such as high voltage transmission converter stations, new energy vehicle electric drive controllers, electromagnetic weapon pulse power supply and so on. At present, thin-film capacitors are developing towards the technical direction of high energy density, voltage resistance, high temperature resistance and so on, which put forward higher requirements for the electrical performance of capacitor films. In this study, ferroelectric polyvinylidene fluoride (PVDF) and polymethyl methacrylate (PMMA) blends were selected as the energy storage polymer matrix, and BaTiO₃ nanoparticles with high dielectric constant and organic molecular semiconductor 6, 6-phenyl C61 methyl butyrate (PCBM) with high electron affinity were used as the doping phase. The high dielectric properties of BaTiO₃ and the ability of PCBM to capture charge are comprehensively utilized to improve the polarization strength and breakdown field strength of the composite medium and significantly improve the energy storage performance. The results show that when the doping content is 3wt%, the composite media has the best comprehensive performance. On this basis, with the increase of PCBM doping content, its energy storage density and charge-discharge efficiency improved significantly. When PCBM doping content is 2wt%, PMMA/PVDF composite medium containing 3wt% BaTiO₃ has excellent energy storage performance. When the electric field is 579.67 kV/mm, the discharge energy density reaches 15.60 J/cm³ and the charge-discharge efficiency is 75.30%. First proposed in this paper, based on a small amount of inorganic high dielectric organic molecules together semiconductor filler modified polymer film energy storage performance of the function, by adding a small amount of BaTiO₃ particles, avoids insulation performance degradation caused by the high content of BaTiO₃, and ensures the BaTiO₃ particle on the properties of composite dielectric permittivity and polarization. At the same time, in order to further improve due to the low dielectric constant substrate with high dielectric constant BaTiO₃ particles between the electric field distortion caused by the breakdown strength degradation, consider joining a certain amount of PCBM in a composite medium, use PCBM electron affinity ability, strong in composite medium build deep traps to capture and carrier, inhibit the transfer of carrier.The breakdown field strength of the composite medium is improved, so as to comprehensively improve the energy storage performance of the composite medium, which provides a new idea for the development of polymer composite medium with excellent energy storage performance.