BACKGROUND The aim of the study was to assess the effect of circRNA CDYL on myocardial angiogenesis after acute myocardial infarction (AMI). MATERIAL AND METHODS We compared changes in circRNA CDYL and myocardial angiogenesis in myocardial infarction tissue and normal heart tissue by establishing a myocardial infarction mouse model to clarify the relationship between circRNA CDYL and changes in myocardial infarction and myocardial angiogenesis. Secondly, we used the RegRNA website to predict downstream miRNA, and we performed gain-of-function and loss-of-function experiments. RESULTS CircCDYL was downregulated in myocardial tissues and hypoxia myocardial cells, and overexpression and downregulation of circCDYL improved and aggravated, respectively, heart function after AMI. CircCDYL overexpression and downregulation can promote and inhibit, respectively, proliferation of cardiomyocytes in vitro. Finally, we found that circCDYL can sponge miR-4793-5p and regulate its expression, and then miR-4793-5p regulates APP expression. CONCLUSIONS CircCDYL can promote the proliferation of cardiomyocytes through the miR-4793-5p/APP pathway.