Abstract: Poly(L-lactic acid) (PLLA)/poly(butylene adipate-co-terephthalate) (PBAT) (80/20, parts by mass)blend was prepared by melting blending. The effect of adding 1 part by mass of chain extender ADR and 1 part by mass of nucleating agent LAK on the crystallization behavior, mechanical properties, rheological behavior and thermal stability of PLLA/PBAT blend were investigated. The results show that after adding chain extender ADR, the crystallinity of PLLA/PBAT blend decreased, while the toughness and impact strength increased, and the compatibility between PLLA and PBAT was improved. After further adding nucleating agent LAK, the crystallinity of the blend increased significantly, the elongation at break and impact strength decreased, but the blend still had good toughness. Chain extender ADR improved the molding processability and heat resistance of the blend, while the improvement effect decreased slightly after further adding nucleating agent LAK. After adding chain extender ADR and nucleating agent LAK simultaneously, PLLA/PBAT blend had both high crystallinity and good properties at the same time.