This research focused on investigating the effects of sevoflurane (Sev) on myocardial autophagy levels after myocardial ischemia reperfusion (I/R) injury via the microRNA-542-3p (miR-542-3p)/ADAM9 axis. Mice underwent 30min occlusion of the left anterior descending coronary (LAD) followed by 2h reperfusion. Cardiac infarction was determined by 2,3,5-triphenyltetrazolium chloride triazole (TTC) staining. Cardiac function was examined by echocardiography. Cardiac markers and oxidative stress factors were evaluated by ELISA. Autophagy-associated factors were detected by western blot. Relationship between miR-542-3p and ADAM9 was tested by dual-luciferase reporter gene assay, RT-qPCR, and western blot. Sev treatment ameliorated cardiac dysfunction, myocardial oxidative stress, and histopathological damages, decreased myocardial infarction size and myocardial apoptotic cells after myocardial I/R injury. Sev treatment elevated miR-542-3p expression and decreased ADAM9 expression in myocardial tissues after myocardial I/R injury. miR-542-3p overexpression could enhance the ameliorative effects of Sev on myocardial injury and myocardial autophagy in I/R mice. miR-542-3p targeted and negatively regulated ADAM9 expression. ADAM9 overexpression reversed the ameliorative effects of miR-542-3p up-regulation on myocardial injury and myocardial autophagy in Sev-treated I/R mice. Sev treatment could ameliorate myocardial injury and myocardial autophagy in I/R mice, mediated by mechanisms that include miR-542-3p up-regulation and ADAM9 down-regulation.