Abstract: OBJECTIVE To explore the anti hypertensive pharmacological mechanism and vascular remodeling mechanism of Tianma Xiongling Zhixuan tablet(TXZT) in spontaneously hypertensive rats(SHR). METHODS SHR and WKY rats were used. The rats were continuously intragastrically administered for 4 weeks, observed and compared the blood pressure values of each group in each week. The levels of eNOS, ET-1, TXA2 and AngⅡ in serum were detected by ELISA. The pathological changes of rat thoracic aorta were observed by HE staining. The expression of MMP-2 and TIMP-2 in aorta was determined by immunohistochemistry, Western blotting and RT-PCR. RESULTS Compared with the model group, TXZT had a significant pharmacological effect on lowering blood pressure(P<0.01 or P<0.05). Compared with the model group, TXZT effectively reduced the levels of serum ET-1, TXA2, AngⅡ and increased the level of eNOS in SHR(P<0.01 or P<0.05), and significantly improved vascular pathological changes. Immunohistochemical and Western blotting showed that TXZT significantly reduced the expression of MMP-2 and MMP-2/TIMP-2 value compared with the model group(P<0.01 or P<0.05). RT-PCR result showed that TXZT significantly reduced the expression of MMP-2 and MMP-2/TIMP-2 value, increased the expression of TIMP-2(P<0.05). CONCLUSION TXZT has significant antihypertensive effect, improving vascular endothelial function and regulating MMP-2/TIMP-2 balance, improve vascular remodeling may be one of its important mechanisms.