Biodegradable plastic bags are bags made of biodegradable plastics.

Biodegradable plastics refer to a class of plastics that are degraded by the action of naturally occurring microorganisms such as bacteria, molds (fungi) and algae. The ideal biodegradable plastic is a polymer material that has excellent performance, can be completely decomposed by environmental microorganisms after being discarded, and is finally inorganicized to become an integral part of the carbon cycle in nature.

"Paper" is a typical biodegradable material, while "synthetic plastic" is a typical polymer material. Therefore, biodegradable plastics are polymer materials that have the properties of both "paper" and "synthetic plastics".

Biodegradable plastics can be divided into two types: completely biodegradable plastics and destructive biodegradable plastics.
Destructive biodegradable plastics currently mainly include starch-modified (or filled) polyethylene PE, polypropylene PP, polyvinyl chloride PVC, polystyrene PS, etc.

Completely biodegradable plastics are mainly made from natural polymers (such as starch, cellulose, chitin) or agricultural by-products through microbial fermentation or synthesis of biodegradable polymers, such as thermoplastic starch plastics, aliphatic polyesters, polylactic acid , Starch/polyvinyl alcohol, etc. all belong to this type of plastic.