OBJECTIVE： To study the anti-coagulation effect and mechanism of fibrinolytic enzyme SNFE in sipuculus nudus， and provide reference for further development of SNFE. METHODS： 40 mice were randomly divided into blank control group （normal saline）， Xueshuantong group （positive control， 15 mg/kg） and SNFE low-dose， high-dose group （15， 30 mg/kg）， 10 in each group. After intravenous injection in tail， tail bleeding time （BT） and clotting time （CT） were respectively determined to investigate the anti-coagulation effect of SNFE. After taking blood in abdominal aorta of rats， test was divided into blank control group， positive control group and SNFE low-mass concentration， medium-mass concentration， high-mass concentration groups （0.25， 0.50， 1.00 mg/mL）. Prothrombin time （PT）， re-calcium time （PRT） （using orokinase as positive drug， 100 000 U/mL）， and maxmum platelet aggregation rate （PAG） in 5 min under adenosine diphosphate （ADP） inducer （using asprin as positive drug， 0.50 mg/mL） were respectively determined， and anti-coagulation effect mechanism of SNFE was analyzed. RESULTS： Compared with blank control group， BT， CT of mice in each group were prolonged， with statistical significance in Xueshuantong group and SNFE high-dose group （P＜0.05 or P＜0.01）. Plasma PT of rats in positive control group， SNFE medium-dose， high-dose groups and PRT in each administration group were significantly prolonged （P＜0.05 or P＜0.01）； and PAG in administration group was significantly reduced （P＜0.01）. CONCLUSIONS： The fibrinolytic enzyme SNFE in sipuculus nudus can play its anti-coagulant effect by inhibiting the activity of coagulation factors in internal and external sources and ADP-induced platelet aggregation.