Objective To research the cardioprotective effect of Astragalus Membranaceus Polysaccharide (AMP) on hemodynamic and oxygen free radicals in myocardial ischemia followed by reperfusion. Methods By using experimental rats cardiac model, rats were divided into 3 groups:CG (control group), IR (Ischemia-Referpusion) and AMP (Astragalus Membranaceus Polysaccharide). Results AMP could promote the restoration of LVSP、?dp/dtmax、CF、CO、SV、SI、CI, and decrease the rising of LVEDP and T value distinctively. The recovery of left ventricular function in AMP group was better than that of the ischemia-reperfusion group, which was accompanied with the significant reduction of oxygen free radicals and increase of superoxide dismutase. Conclusion AMP could attenuate ischemia- reperfusion injury and ameliorate functional recovery in isolated rat hearts.