Objective To investigate the change of serum von willebrand factor(vWF)level in the different stages of diabetic nephropathy and its significance. Methods 50 healthy subjects and 150 patients with type 2 diabetes mellitus were enrolled in this study. Diabetic patients were further divided into three subgroups according to their urinary albumin excretion rate(UAER): 56 patients with normal UAER,49 patients with microalbuminuria and 45 patients with clinical proteinuria. Serum vWF concentration was measured with emzyme linked immunosorbent assay (ELISA) method. Results vWF concentration was significantly higher in patients with type 2 diabetes mellitus than that in normal controls. Serum vWF concentration increased with the elevation of UAER. Serum vWF level was positively related with UAER, blood creatine and course of disease independently. Conclusion Serum vWF concentration increased in the patients with type 2 diabetes mellitus and the increased extent of vWF was consistent with the severe degree of diabetic nephropathy.