Biodegradable composite film and preparation method thereof

The invention provides a biodegradable composite film, which is prepared from a plasticizer, a reinforcing agent, a crosslinking agent, egg white protein and nano SiOx which serve as raw materials, wherein the plasticizer consists of glycerol and polyethylene glycol 400 with volume ratio of 3 to 1; the reinforcing agent is CMC-Na (sodium carboxymethylcellulose); and the crosslinking agent is epichlorohydrin. The biodegradable composite film has excellent mechanical performance and isolation performance, has the use performance of a plastic coating film, and can completely replace a conventional plastic package film.