Abstract: Polylactic acid (PLA) is a biodegradable and bio-based aliphatic polyester. It has received extensive attention due to its great environmental and economic value. As a biodegradable material, Polylactic acid (PLA) has poor impact toughness, resulting in a limitation of application. Blending PLA with polybutylene adipate terephthalate (PBAT) can significantly enhance its toughness. PLA/PBAT composite films, as a biodegradable material, is widely used due to its advantages of abundant raw materials, low cost, and environmental friendliness. This article outlines the different preparation methods and current research status of PLA/PBAT composite membranes. The modification technologies of composite membranes, including inorganic fillers, chain expansion and compatibilization, crosslinking agent modification, starch modification, and synergistic modification are summarized. Finally, the application and development prospect of PLA/PBAT composite films in food packaging is introduced, which provide theoretical references and new ideas for future research on PLA/PBAT films in food packaging.