Myocardial infarction (MI) is characterized by the sudden reduction in myocardial blood flow and remains the leading cause of death worldwide. Because MI causes irreversible damage to the heart, discovering drugs that can limit the extent of ischemic damage is crucial. Liensinine (LSN) is a natural alkaloid that has exhibited beneficial effects in various cardiovascular diseases, including MI; however, its molecular mechanisms of action remain largely unelucidated. In this study, we constructed murine models of MI to examine the potential beneficial effects and mechanisms of LSN in myocardial ischemic injury. Murine models of MI in wild-type and cardiomyocyte-specific β-catenin knockout mice were used to explore the role of LSN and Wnt/β-catenin signaling in MI-induced cardiac injuries and inflammatory responses. The administration of LSN markedly improved cardiac function and decreased the extent of ischemic damage and infarct size following MI. LSN not only prevented excessive inflammatory responses but also inhibited the aberrant activation of Wnt/β-catenin signaling, two factors that are critically involved in the exacerbation of MI-induced injury. Our findings provide important new mechanistic insight into the beneficial effect of LSN in MI-induced cardiac injury and suggest the therapeutic potential of LSN as a novel drug in the treatment of MI.