Objective: To observe the changes of coagulation and fibrinolysis function in human umbilical cord vein endothelial cells (HUVEC) induced by recombinant human tumor necrosis factor-α (rh TNF-α) and the effect of Naotaifang extract(脑泰方，NTE) on it. Methods: Cultured HUVEC is randomly divided into six groups: Control group, NTE control group (only 2 g/L NTE), rhTNF-α group (100μg/L rhTNF-α), and low-dosage, middle-dosage and high-dosage NTE group (100 μg/L rhTNF-α and 0.67g/L, 2 g/L, 6 g/L NTE). The coagulation activity of frozen-dissolved HUVEC, yon Willebrand factor (vWF) content in the conditioned medium and tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor (PAI) activity were to be detected after 24 hrs. Results: Compared with the control group, PAI activity were enhanced, vWF release markedly increased in conditioned medium of TNF-αgroup (P＜0. 01) and the frozen-dissolved HUVEC markedly shortens the rabbit plasma prothrombin time, and the above changes could be significantly inhibited by the 3 dosages of NTE (P＜0. 05, P＜0.01). Conclusion; NTE is effective in inhibiting the coagulation activity of the HUVEC non-stimulated or stimulated by rhTNF-α to enhance the vWF release, and to adjust fibrinolytic function, and mainly to inhibit the PAI activity.