The invention discloses a polyvinylidene fluoride film and a preparation method thereof. The film is prepared from polyvinylidene fluoride, auxiliary materials, inorganic filling materials, anti-yellowing agents, polyisobutene, sodium methyl silicate, microcrystalline wax, trichloro ethylene, maleic anhydride and ultraviolet light absorbers. According to the preparation method, the polyvinylidenefluoride, the auxiliary materials, the inorganic filling materials, the polyisobutene, the sodium methyl silicate, the microcrystalline wax, the trichloro ethylene and the maleic anhydride are mixed;then, the anti-yellowing agents and the ultraviolet light absorbers are added; uniform mixing and sheet casting are performed; next, the cast sheets are preheated; longitudinal stretching is firstly performed; then, transverse stretching is performed. The polyvinylidene fluoride film and the preparation method have the obvious advantages that the polyvinylidene fluoride film obtained through biaxial stretching has excellent weather resistance, gas blocking performance and waterproof performance; in addition, degradation and yellowing cannot easily occur under the sunlight irradiation in a short period; excellent UV-resistance performance, high transparency and high mechanical property are realized.