In this work, different contents (10-40 wt%) of poly(butylene succinate) (PBS) were introduced into poly(lactic acid) (PLA) through the common melt compounding processing. The microstructure and morphologies of the blends were investigated through differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD) and scanning electron microscope (SEM). The results showed that the presence of PBS neither induces the crystallization nor enhances the crystallinity of PLA matrix, and completely amorphous PLA was obtained in all samples. PBS exhibited dispersed particles in the PLA matrix and there were clear gaps between components. The hydrophilicity of samples was evaluated by measuring contact angles. The results demonstrated that adding PBS improved the hydrophilicity of samples. The hydrolytic degradation measurements were carried out at 37 A degrees C in alkaline solution. The results showed that the presence of PBS accelerated the hydrolytic degradation of PLA matrix. Specifically, the higher the content of PBS was, the bigger the weight loss per unit area of sample was. The hydrolytic degradation mechanism was then analyzed.