Abstract: With the advancement of science and technology, energy storage capacitors are gradually developing towards miniaturization and high temperature, especially in electrical energy vehicles, oil and gas exploration and other fields. However, as the temperature increases, the dielectric properties of polar dielectric materials that can achieve high energy storage characteristics are severely reduced, so they cannot be used in high temperature environments. High-temperature polymers can be used in high temperature environments, but it is difficult to obtain high energy storage density to achieve the miniaturization goal of energy storage capacitors because of their relatively low dielectric constant. Therefore, the semi-interpenetrating polymer network structure of PVDF and P(MMA-EGMDA) was studied by introducing ethylene glycol dimethacrylate(EGDMA) with double bonds based on the copolymerization-blending method to strengthen the physical connection between PVDF and P(MMA-EGDMA) and improve the compatibility between the two. At the same time, the crosslinked structure is used to improve the temperature stability of the dielectric properties of the composite material. Among them, the energy storage density and efficiency of SIPN PVDF/P(MMA-EGDMA)(42.9/57.1) are controlled at 6.9~7.6 J/cm³ and 81%~59.7% under the same electric field strength in the range of 30~120℃, and the relative change rate of energy storage density with temperature is 11.2%, which is higher than that of most ferroelectric polymers.