Abstract: Objective To study the effect of irbesartan pretreatment on myocardial ischemia/reperfusion(I/R) injury in rats and its possible mechanism. Methods Thirty-eight healthy male SD rats were randomly divided into sham group(group A), I/R injury group(group B), and irbesartan pretreatment group(group C). A rat myocardial I/R injury model was established.Myocardial tissue samples were stained with TTC to observe the myocardial infarction size and myocardial cell structure. Serum malondialdehyde(MDA) concentration was measured by colorimetry, TNI content in rats was assayed by biochemical test, and serum tumor necrosis factor(TNF-α) and interleukin-6(IL-6) concentrations were measured by ELISA. Results The myocardial infarction size was smaller, the inflammatory cell infiltration was milder, the myocardial cell structure was better, and the serum MDA TNI, IL-6 and TNF-α concentrations were lower in group C than in group B(P< 0.05, P< 0.01). Conclusion Irbesartan pretreatment protects myocardium against I/R injury possibly by reducing the synthesis or releasing of inflammation factors.