The invention relates to a method for preparing a methyl cellulose and lipid packaging film, and belongs to the technical field of food packaging. Methyl cellulose and a lipid are used as main film forming materials, and a plasticizing agent is used as an accessory material. The preparation method comprises the following steps: (1) weighing methyl cellulose, adding a hot ethanol water solution into the methyl cellulose, and adding the plasticizing agent and the lipid after the methyl cellulose is fully dissolved to form a mixed film liquid; (2) performing a synergistic processing of microwave and ultrasonic on the mixed film liquid, forming a film through tape casting, drying and taking out the film to obtain the methyl cellulose-based composite food packaging film. Compared with the prior art, the lipid-containing methyl cellulose film liquid is subjected to the synergistic processing of microwave and ultrasonic to prompt the crystallization of a lipid substance on the surface of a methyl cellulose substrate through a self-association effect, so that a dense lipid layer is formed and a double-layer structure is formed finally. The double-layer film prepared by the method is non-toxic, edible and biodegradable, can be formed by only one tape casting, is simple in film preparation process, meanwhile, has excellent mechanical and moisture-resistant properties, and can be used as a food inner package.