Aliphatic polyesters, such as poly(lactic acid)(PLLA) and poly(butylenes succinate)(PBS), exhibit superior biodegradability and good comprehensive properties. However, their insufficient mechanical properties of aliphatic polyesters, especially their poor impact strength, have prevented them from being used in many applications . Therefore, various polymer blends have been produced in order to improve the physical properties and extend the application fields of aliphatic polyester. Blending aliphatic polyesters with non-biodegradable polymers might improve the mechanical properties effectively but the degradable properties of the material would be undermined. Aliphatic polycarbonates (APCs), as another important class of biodegradable polymers, are widely used in the areas of packaging materials, drug carriers and tissue engineering for their favorable biodegradability, biocompatibility and non-toxicity. During previous work, our team successfully synthesized high-molecular-weight Poly(butylenes carbonate) (PBC) for the first time via a successive two-step polycondensation. Due to the flexibility of the polymer chains and its crystallizability, PBC possesses excellent impact resistance and satisfactory tensile strength. Therefore, blending aliphatic polyesters with PBC is expected to improve the impact strength of aliphatic polyesters while hardly sacrificing other properties, and at the same time a fully biodegradable material can be prepared. In the present paper, fully biodegradable blends of aliphatic polyesters and PBC were prepared and the miscibility, thermal properties, crystallization behavior and mechanical properties of aliphatic polyesters /PBC blends were investigated by scanning electron microscopy, phase contrast optical microscopy, differential scanning calorimetry, wide angleX-ray diffraction and mechanical properties tests. The impact strengths of PLLA and PBS were improved significantly by blending with PBC.