Aim To explore the effect of astragalus polysaccharides （APS） on myocardial hypertrophy in rats induced by isoproterenol （ISO）. Methods 15 mg/（kg·d） ISO were used as myocardial hypertrophy models by intraperitoneally injection. 60 SD rats were randomly assigned to six groups, 10 rats for each group: the control group, ISO group, ISO＋APS 200 mg/（kg·d） group, ISO＋APS 400 mg/（kg·d） group, ISO＋APS 800 mg/（kg·d） group and ISO＋propranolol 40 mg/（kg·d） group. Administered groups were continually intraperitoneally injected administration for 3 weeks, and ISO were intraperitoneally injected as long as 2 weeks in the day after that. After 3 weeks, at the end of the treatment period, hemodynamic parameters were observed, and pathological section by HE staining. The expression of free fatty acid （FFA）, ATP, ADP, AMP were quantified by ELISA. The expression of atrial natriuretic factor （ANF）, PGC-1α mRNA were determined by RT-PCR, the expression of PGC-1α protein were determined by Western blot in the tissue. Results Compared with control group, ISO group markedly elevated HMI, LVMI, LVEDP level and decreased LVSP level, meanwhile the expression of ANF mRNA were increased and the expressions of PGC-1α mRNA and protein decreased. Compared with ISO group, the APS for different dose groups dependently improved hemodynamic parameters, ATP/AMP and ATP/ADP ratio and PGC-1α mRNA and protein expressions. Conclusions APS can improve cardiac hypertrophy induced by ISO, which maybe improve energy metabolism by PGC-1α.