The invention relates to a biodegradable thermoplastic starch resin film. The composition and content of raw materials are as follows: thermoplastic starch 40-52%, metallocene 8-16%, low-density polyethylene 20-30%, smooth 3-5% of agent, 4-6% of high-density polyethylene, 5-8% of pigment; the preparation method of the biodegradable thermoplastic starch resin film comprises the following steps: mixing thermoplastic starch, metallocene, low-density polyethylene, smooth Agents, high-density polyethylene, and pigments are mixed by the mixer according to the above mass percentages, added to the film blowing unit, and plasticized, extruded, blown, drawn, and rolled by the blown film extruder, and then blown. Biodegradable thermoplastic starch resin film; Compared with the prior art, the present invention adopts special raw materials, such raw materials are green and environment-friendly bio-polyethylene, etc., so that the film produced can be biodegradable, bio-environmental, and reduce carbon dioxide emissions.