Polylactic acid (PLA) is a new type of biodegradable material made from starch raw materials proposed by renewable plant resources such as corn. Starch raw material is saccharified to obtain glucose, and then fermented from glucose and certain strains to produce high-purity lactic acid, and then chemical synthesis method is used to synthesize polylactic acid with a certain molecular weight. It has good biodegradability and can be completely degraded by microorganisms in nature after use, and finally generates carbon dioxide and water, which does not pollute the environment, which is very beneficial to protect the environment and is recognized as an environmentally friendly material. The treatment method of ordinary plastics is still incineration and cremation, which causes a large amount of greenhouse gases to be discharged into the air, while polylactic acid plastics are buried in the soil to degrade, and the carbon dioxide produced directly enters the soil organic matter or is absorbed by plants, and will not be discharged into the air. Does not cause greenhouse effect