【Abstract】Objective To investigate the role and the possible mechanism of pyroptosis in ischemia/reperfusion(I/R)injury. Methods 75 male SD rats were randomly divided into Control group, I/R group(underwent I/Rtreatment), YVAD group (pretreated with ZYVADFMK), YVAD+I/R group (pretreated with ZYVADFMK before I/Rtreatment), MCC950 group (pretreated with MCC950) and MCC950+I/R group (pretreated with MCC950 before I/Rtreatment). In order to observe whether I/Rtreatment could cause pyroptosis, the positive rate of Tunel staining, the expression of NLRP3 inflammasomes, caspase1 , IL1β and GSDMDN in the each groups were detected.Results The positive rate of TUNEL staining, infarct size, the expression of NLRP 3, caspase 1, IL 1 β and GSDMD n in ischemia/reperfusion group were significantly higher than those in control group (all P < 0.05). The positive rate of TUNEL staining, infarct size, expression of caspase 1 (mature body), IL1β and GSDMD n in YVAD+I/R group were higher than those in control group, but lower than those in I/R group (all P＜005). After inhibition of NLRP3 expression, the positive rate of TUNEL staining, myocardial infarction size, caspase 1, IL1β and GSDMD n expression levels in MCC950+I/R group were higher than those in control group, but significantly lower than those in I/R group (all P＜〖JP2〗005). Conclusion Myocardial ischemia/reperfusion injury in rats is related to NLRP3 inflammasome mediated pyroptosis.