Abstract: PLA/PBAT/methyl methacrylate-silicone-styrene copolymer (S-2001) blends were prepared by melt extrusion with a twin-screw extruder, and the effect of S-2001 content on the microstructure, rheological behavior and mechanical properties of the blends were investigated by using a scanning electron microscope, rotational rheometer and electronic universal testing machine. The results indicated that the addition of S-2001 reduced the size of dispersed particles but improved the interfacial adhesion between the PLA and PBAT phases. Furthermore, the storage modulus, loss modulus and complex viscosity of the blends were also improved, and their Marangoni stress relaxation was enhanced gradually. When the 9 phr of S-2001 was incorporated into the blends, the notched impact strength increased by 596.6 % from 5.8 kJ/m2 to 40.4 kJ/m2, suggesting that S-2001 acts as an impact modifier as well as a compatibilizing agent.