The development in packaging materials shows a diversified trend, while a large number of non-recyclable and non-degradable plastic waste has been produced, causing serious harm to the ecological environment. Polylactic acid (PLA) is a new kind of completely biodegradable polymer material, which has good mechanical properties, biocompatibility and degradability, and has become a hot spot in the research and application of packaging materials. However, the barrier performance of traditional PLA cannot meet the application requirements, which limited its application scope. Therefore, by improving the crystallinity and crystal morphology, polymer blending, nanoparticle blending to modify the barrier properties of PLA, its breakthrough and transformation applications in all walks of life can be promoted. With the development in modification processing technology, PLA will be widely used in medical materials, packaging materials, building materials, daily necessities and other fields.