Polylactic acid-graft-glycidyl methacrylate (PLA-g-GMA) was prepared by torque rheometer as the compatibilizer of PBAT and PLA blends. The grafting rate of PLA-g-GMA at different proportions of PLA and GMA were analyzed by FTIR and 1H-NMR. The effects of the compatibilizer on crystallization and microstructure of PBAT/PLA blends were studied by DSC and SEM. The results showed that GMA was successfully grafted onto PLA. When the amount of GMA was 20% of the total mass, the grafting rate of PLA-g-GMA reached 6.44%. The addition of compatibilizer improved the crystallization structure of PLA in the blends during cooling, and the cold crystallization peak disappeared when the addition amount was 6% of the total mass. When the mass fraction of the compatibilizer was 4%, the crystallization temperature of PBAT/PLA blends decreased from 75.4 ℃(without compatibilizer) to 68.0 ℃. The addition of PLA-g-GMA reduced the initial crystallization rate constant of the blends from 0.83(without compatibilizer) to 0.68(when the mass fraction of compatibilizer was 10%), inhibited PLA from forming crystal nucleus. But it increased the second stage crystallization rate constant from 1.28(without compatibilizer) to 1.38(when the mass fraction of compatibilizer was 2%), which promoted the growth of PBAT crystals; The compatibilizer reduced the degree of detachment between PLA and PBAT in the brittle fracture section. When the mass fraction of compatibilizer was 8%, the strength of the PBAT/PLA blend fiber increased from 0.25 cN/dtex to 0.33 cN/dtex.