Objective:To study the effect of verapamil on platelet aggregation, thrombogenesis and the potential mechanism. Methods:The SD rats were injected the different concentration of verapamil, Aspirin-DL-Lysine and the saline solution for 7 days(i.p), respectively. After the administration, the platelet aggregation was measured by aggregometry, the thrombogenesis was tested by the pathway of arteria carotis communis-external jugular vein, and the concentration of NO was evaluated with the kit of nitrate reductase. Results:Verapamil exhibited a dose-dependent inhibitory effect on platelet aggregation and thrombus formation in rats. Conclusion: Verapamil imporoving the function of platelet was through elevating the NO level.