Abstract: Objective:To explore the effect of Pollen Typhae on thrombosis.Methods: Thirty-five rats were divided into five groups and thrombosis model was set up.In the experimental group,Pollen Typhae was injected into the stomach for admi-nistration for 7 days;the positive control group was administered with aspirin;the blank control group was only administered with physiologic saline,and the wet weight of thrombus,the inhibitory rate and the blood flow velocity were compared.Results: Pollen Typhae could inhibit the formation of the thrombosis,the wet weight of thrombus were declined in the experimental group,the inhibitory rate was 15%～43%;and Pollen Typhae could change the blood flow velocity.Conclusions: Pollen Typhae have good antithrombotic effect.