Abstract: Two kinds of biodegradable polymers, poly(propylene carbonate)(PPC) and poly(butylenes succinate)(PBS), were used as slow-released film for urea, and ratios of PPC/PBS in solution are adjusted in range of 12∶0-0∶12 After evaporating the solvent, the PPC/PBS membranes were obtained in various ratios. The PPC/PBS-coated slow-released urea was prepared by spouted-spraying method, nitrogen release was investigated by Ultraviolet Spectrophotometry method, and scanning electronic microscopy(SEM) was used to observe the structure of the coating film. The results show that the flexible and compatible membrane is the best under the ratio of 7∶5 When the weight ratio of PPC∶PBS is about 7∶5, the composite material possesses strong film characteristic, comparable and flexible. The PPC/PBS film is found suitable to the rugged surface of urea and combined tightly with the surface of urea. The PPC/PBS coated urea shows remarkable controlling function of urea nitrogen release. These results also prove that reducing envelope time or increasing resin quality can enhance the quality of controlled release effect.