Immobilization of rHir to polyurethane surfaces was studied. A PU1 solution with carboxyl acid in hard segment was cast on PU or Chro surfaces and the carboxyl acid content on the surfaces was measured by methylene blue adhesion. BSA was covalently linked on carboxylated surfaces by EDC and the BSA content on the surfaces was measured by substration of FT-ATR-IR spectra. rHir was immobilized to BSA lay on polymers by EDC and the r-Hir content on surfaces was measured by isotopes tagging. The results showed that the carboxyl acid content on CPU and C-Chro surfaces was 3.77 and 3.03 mmol/m² respectively, the BSA content on CPU-BSA and C-Chro-BSA surfaces was 426 and 262 mg/m² respectively, the rHir content on CPU-BSA-rHir and C-Chro-BSA-rHir surfaces was 716.7 and 691.1 μg/m² respectively. Thrombin activity inhibition test indicated that the KPTT、PT、TT times of rHir-immobilized specimens were prolonged as compared with controlled, the antithrombin activity on rHir-immobilized PU and Chro surfaces was increased obviously and their antithrombogenicity was improved effectively.