Abstract: PLA is a linear aliphatic thermoplastic polyester. Polylactic acid synthesized from plant resources has strong biodegradability. The synthesis, processing and application of PLA are of great significance to the production of degradable mulch film. Polylactic acid（PLA） mulching film not only has full biodegradability, non-toxic and good biocompatibility, but also has high strength,high modulus, good air permeability and CO₂ permeability, and also has the characteristics of odor isolation. Virus and mold attached to the surface of PLA film can promote the degradation of PLA mulching film.