The invention discloses an electrostatic spinning capacitor diaphragm material capable of enhancing the strength through silica sol cooperating with a polymer. The material is prepared from, by weight, 80-83 parts of polyvinylidene fluoride, 20-22 parts of polymethyl methacrylate, an appropriate amount of DMF, 2-3 parts of nano boehmite, 0.8-1 part of a silane coupling agent KH550, an appropriate amount of deionized water, 2-3 parts of nano magnesium aluminate, 5-6 parts of polyurethane, 6-7 parts of polythioetherimide and 5-6 parts of silica sol. According to a series of process treatment, polyurethane, polythioetherimide and silica sol are compounded and then added into an electrostatic spinning solution, a fiber membrane obtained through spinning can achieve the breaking strength, heat resistance, liquid absorbing ratio and porosity; meanwhile, due to addition of nano magnesium aluminate, the high dielectric constant is achieved, nano magnesium aluminate is added into a polymer solution, an ion channel is easy to form, and the electrical conductivity of ions is increased.