Abstract: The waterborne polyurethane (WPU) was synthesized by using trimers of 1,6-hexamethylene diisocyanate(HDI). WPU film was dipped in solution of sulfated chitosan (SCS) to prepare WPU/SCS composite films. The obtained films were characterized by FT-IR, TGA and DSC. The hemocompatibility of the composite membrane was studied by dynamic coagulation test. The results showed that the WPU was combined with SCS through covalent bonds,that the composite membrane had a Tg of 53.2 ℃ and a thermal decomposed temperature of 300-400 ℃,and that the composite membrane had better hemocompatibility than WPU. WPU/SCS composite membrane is a potential biomedical material.