Abstract: Polylactic acid is an aliphatic polyester with excellent biocompatibility, biodegradability and bioabsorbability, and has been extensively applied in biomaterials. The principal raw material, lactic acid, is derived from corn and other natural materials. It is non-irritating and has no toxic effects, and is thus safe for human use. Because of its biodegradability, it is also environmentally friendly. Polylactic acid shows high plasticity and is easy to form, and is considered to be the most promising biomedical and packaging material. The mechanical, thermal and degradation properties of polylactic acid are improved by modifications. It is thus suitable for application as a modern biomedical material and has been widely used in various applications. In the present paper, we discuss recent advances in the medical applications of polylactic acid, including its use in resorbable medical sutures, dental materials, ophthalmic implant materials, fracture fixation devices, tissue engineering, delayed release drug carriers and clinical applications. Finally, we discuss the future prospects for the research and application of polylactic acid biodegradable materials. This paper also provides effective information to help researchers develop new medical materials to overcome the current limitations of polylactic acid-based materials.