Purpose : The Purpose of this research was to investigate the effects of antithrombotic activities of Wuslsan (WSS). Methods : Measure the effect which was given to blood flow rate through the regular volume of glass tube after the blood was diluted five times with ACD soulution. Antithrombotic effect was calculated as a percentage of the experimental animal figure protected from the paralysis of hind legs or death of the mouse that is caused from the administration of platelet aggregation regent. Being classified one group of eight mice, each of them was divided into Normal, Control, and WSS. The normal group supplied a saline solution and the control group brought the dextran extravasated blood after an hour of administering the saline solution. Also WSS was dissolved in 2ml saline solution and then we dosed it to the experimental mice with Oral Zonde one day before the experiment. After that, the mice were abstained from food. And then we gave a measured amount of it before an hour. Finally, it gave rise to dextran extravasated blood in the same way as the Control group. Results : The results were obtained as follows. WSS inhibited platelet aggregation induced by ADP and epinephrine significantly as compared with the control group. WSS showed fibrinolytic activity insignificantly as compared with the control group. WSS increased blood flow rate significantly as compared with the control group in vitro. WSS inhibited pulmonary embolism induced by collagen and Epinephrine(inhibitive rate is 37.5%). WSS increased number of platelet and fibrinogen amount significantly, and shortened PT and APTT as compared with the control group in thrombus model induced by dextran. Conclusion : WSS is effective antithrombotic activity from experimental result.