Objective To investigate the effect of Xiefei Lishui Granules on spontaneous hypertension rats（SHR） through testing the level of Ang I,Ang II,ACE,renin and aldosterone（ALD）by ELISA to explore the mechanism of anti-hypertensive effects of Xiefei Lishui Granules.Methods 50 SHR of 13-week old were randomly divided into model group,high dose,medium dose,and low dose of Chinese medicine group and captopril group,with 10 rats in each group;10 Wistar-Kyoto（WKY） rats as normal control group.The blood pressure of the tail artery of rats was measured before the experiment and 4 weeks later.The level of Ang I,Ang II,ACE,renin and ALD were tested and analyzed respectively by ELISA after 4 weeks.Results Compared with the model group,the blood pressure of high dose group,medium dose group,low dose group of Chinese herbal medicine and captopril group were decreased after 4 weeks（PP<0.01）.The blood pressure of medium dose group and captopril group showed no significant statistical difference after 4 weeks.Compared with the model group,the level of serum renin and Ang I of captopril group,high dose group,medium dose group and low dose group of Chinese herbal medicine were significantly decreased with the difference statistically significant（P<0.01）.Compared with the model group,the level of ALD and Ang II of captopril group and medium dose group were much lowered with the difference statistically significant（P<0.01）,the level of ALD and Ang II of the high dose group and low dose group of Chinese medicine were lowered with the difference statistically significant（P<0.05）.The level of Angiotensin converting enzyme（ACE） showed no difference between the groups.Conclusion Xiefei Lishui Granules can effectively reduce the blood pressure of tail artery of SHR,and the mechanism might be the effect of inhibiting of the renin-angiotensin-aldosterone system.