Aim To study the effect of Dracocephalum heterophyllum Benth flavonoid (DHBF) on cardiac hypertrophy of hypertension rats. Methods Hypertension rats model was established by renal artery stenosis surgery (two kidneys one clip). Six weeks after the surgery, the rats were randomly divided into 5 groups Sham group; Model group; DHBF high dose group (DHBF_H ); DHBF low dose group(DHBF_L ) and Captopril group. After treated for 6 weeks, the echocardiography, histological examination of the heart were performed. The levels of IL-1beta,TNF-alpha, the relative expression of MMP-9 mRNA and TIMP-1 mRNA were detected by real-time PCR. Results After 6 weeks treatment, the wall thickness of left ventricle, myocardial cell size and interstitial fibrosis of the myocardial cells in the left ventricl in Model group were significantly increased compared with those in sham group(P<0.01). Treatment with DHBF_H for 6 weeks significantly attenuated left ventricular hypertrophy(P<0.01). Biochemical testing revealed that the levels of IL-1beta,TNF-alpha, the expression of MMP-9 and TIMP-1 reduced after treatment with DHBF, the levels of them were significantly increased in model group(P<0.01). Conclusions The results suggest that DHBF_H treatment significantly inhibits the cardiac hypertrophy and interstitial fibrosis in hypertension rats. Its possible mechanisms are via lowering blood pressure, reducing the level of IL-1beta,TNF-alpha and balancing the expression of MMP-9/TIMP-1.