3D printing technology is known as the core technology of “the third industrial revolution”. Poly (lactic acid) (PLA) is a new type of biodegradable thermoplastic resin, which is renewable. It has a wide range of raw materials. It also has the properties of high strength, good biocompatibility, excellent mechanical properties, thermoplastic and transparency. Hydrotalcite (HT) was synthesized by coprecipitation method and modified to prepare the HT/PLA composites. The results show that the structure of HT is good. After KH550 surface modification, a large number of OH and Si-O groups are introduced into PLA surface. TG results show that the HT sample has good thermal stability. Compared with pure PLA, the glass transition temperature and crystallization temperature of HT / PLA composites decreases, while the melting temperature increases.