Abstract: AIM:To investigate the effects of jianxin granules on cardiac performance in rats with chronic congestive heart failure and the possible mechanism. METHODS: Animal models of heart failure were induced by clipping the abdominal aorta. Thirty two rats were randomly divided into four groups: shamoperated (sham) group, aortic stenosis (model) group, jianxin granules group, and benazepril group. Drugs were administered intragastrically from the 13th week after surgery and rats were examined after 12 weeks’ treatment. Hemodynamic parameters (including ±dP/dtmax and LVEDP) and the ratio of left ventricle (LV) to body weight（LVMI）were determined. SERCA2a mRNA and protein expression were assessed by RTPCR and Western blot techniques, respectively, and interstitial collagen volume fraction (CVF) was evaluated by picrosirus red staining. RESULTS: LVMI and LVEDP significantly increased and ±dP/dtmax decreased in model rats. Both jianxin granules and benazepril medication reversed these effects. SERCA2a expression was downregulated and CVF significantly increased in the model group compared with those in sham control group. Jianxin granules and benazepril treatment upregulated SERCA2a expression and suppressed CVF compared with those in model rats. CONCLUSION: Jianxin granules improve myocardial function, which may result from its upregulation of SERCA2a expression and amelioration of myocardial fibrosis in rats with chronic congestive heart failure.