Abstract: The present invention discloses a low cost bio-based full degradable film and preparation method thereof, the ratio of each component in parts by mass of the film is as follows: 15-25 parts of a polyglycolic acid, 25-35 parts of corn starch, 35-55 parts of poly(butylene adipate-co-terephthalate), 5 parts of a compatilizer, 3.75-12.25 parts of a starch plasticizer, 0.5-0.7 part of citric acid, 0.75-1.25 parts of acetyl tributyl citrate, 0.3-0.5 part of maleic anhydride, 0.2 part of antioxidant 164, and 0.2 part of 2-(2?-hydroxyl-5?-methylphenyl)benzotriazole. The low cost bio-based full degradable film provided by the present invention has a bio-based content, which can reach 30% or more, a lower cost, and a tensile strength exceeding a traditional PE thin film, and has very important significance for solving the problem of “white pollution” and promoting the popularization and application of full biodegradable materials.