Polylactic acid (PLA) is a new kind of biobased and renewable biodegradable material, which is made from starch proposed by renewable plant resources (such as corn and cassava). Starch raw materials obtained glucose through saccharification, and then fermentation of glucose and certain strains to produce high purity lactic acid, and then through chemical synthesis method to synthesize polylactic acid of a certain molecular weight. It has good biodegradability.