Objective To investigate the influence of enzymatic and hydrolytic degradation on the biodegradability of PBS. Methods PBS films were placed in the enzyme solution and phosphate buffer solution for enzymatic degradation and hydrolytic degradation. Biodegradability of PBS was studied by means of thermogravimetry ( TG) , X-ray diffraction ( X-RD) , scanning electron microscopy ( SEM) and weight loss rate. Results TG and X-RD analysis showed that the thermal stability of PBS was reduced from 308. 83 ℃ to 282. 85 ℃ , and the crystallinity of PBS presented a certain degree of decline after enzymatic degradation, while the thermal stability of PBS first decreased and then increased during the hydrolytic degradation period and the crystallinity of PBS remained unchanged. SEM and weight loss results confirmed that the enzymatic degradation occurred at the surface of the PBS film and the weight of film decreased with time, the weight loss was 33. 2% after 10 weeks of degradation.However, hydrolytic degradation of films occurred throughout the whole polymer matrix and the weights of PBS films did not change significantly, the weight loss was only 4. 7% after 20 weeks of degradation. Conclusion The enzymatic degradation was quite different from the hydrolytic degradation. Enzymatic degradation underwent surface erosion while hydrolytic degradation showed bulk erosion.