Objective: To research the huoxuehuayu effects of different cultivated populations of safflower, and probe the intraspecific variance of safflower, and provide the basis for evaluation of the crude drug and breeding of good cultivated populations. Methods: Percentage of restraining platelet aggregation, prothrombin time and partial thromboplastic time were measured to compare the huoxuehuayu effects of different populations of safflower. Results: The huoxuehuayu effects of different populations were significantly different(P<0.01). The effects on restraining platelet aggregation from strong to weak were Jimusa′er population, Jianyang population, Xinxiang population and Weishan population (P>0.05 between the last two populations).The effects on prolonging prothrombin time and partial thromboplastic time from long to short were Weishan population, Jianyang population, Xinxiang population and Jimusa′er population(P>0.05 between the last two populations). Conclusion: The huoxuehuayu effects of different cultivated populations of safflower were different because of the different indexes. Jimusa′er population was best on restraining platelet aggregation. Weishan population was best on prolonging prothrombin time and partial thromboplastic time.