Aim To investigate the changes of myocardial injury and cardiac function in severe patients with coronavirus disease 2019 (COVID-19). Methods Retrospective analysis was performed on the clinical datas of 36 COVID-19 patients. According to clinical classification, the patients were divided into severe group (n＝4) and mild group (n＝32). Collect the patients's general clinical datas and the status of the consolidated basis of cardiovascular disease, the patients' serum creatinie, myoglobin, lactic dehydrogenase(LDH), creatine kinase (CK), creatine kinase isoenzyme (CK-MB), troponin T (cTnT),Nü end of B-type natriuretic peptide (NT-ProBNP), c-reactive protein (CRP) levels, and echocardiography measurements of left ventricular and right ventricular function. Results The in-hospital time in the severe group was significantly longer than that in the mild group (Z＝－3.183, P＝0.001), the incidence of diabetes (χ²=13.056, P＜0.001), the serum levels of myoglobin(t＝5.284,P＜0.001), CK(Z＝－2.267,P＝0.023), CK-MB(Z＝－2.140,P＝0.032), cTnT(Z＝－2.134, P＝0.037), CRP(Z＝－1.892,P＝0.041), NT-ProBNP(Z＝－2.467,P＝0.014) and right ventricular Tei index(t＝5.256,P＝0.023) were significantly higher than those in the mild group. There were no significant differences in LVDd, LVSd, LVEF and left ventricular Tei index between the two groups. Conclusion The morbidity of diabetes in patients with severe COVID-19 was significantly higher than that of patients with mild COVID-19, while patients with severe COVID-19 had some extend of myocardiol injury and impaired right ventricular function.