The invention relates to an impact-resistant and high-efficiency flame-retardant decorative film and a preparation method thereof. The decorative film is prepared from the following raw materials in parts by weight: 80-120 parts of PVC resin powder, 30-50 parts of plasticizer, and 0.5-5 parts of soybean oil , 18-45 parts of composite flame retardant, 0.5-5 parts of formaldehyde absorbent, 0.5-5 parts of environmental stabilizer, 0.5-5 parts of smoke suppressant, and 5-15 parts of nano-calcium powder. Using PVC resin powder as the main raw material, adding plasticizers, composite flame retardants, soybean oil, formaldehyde absorbents, stabilizers, smoke suppressants, and nano-calcium powders as functional additives, through high-speed stirring and mixing, molding extrusion, The decorative film is produced by first rolling machine plasticizing, second rolling machine plasticizing, filtering, calendering, cooling, and coiling. The present invention optimizes the production process parameters by optimizing the formula, and the prepared decorative film has the characteristics of excellent flexibility, high-efficiency flame retardancy, environmental protection, high compliance, good impact resistance, etc., and also has the effect of purifying formaldehyde , has a good market prospect.