Aim To investigate the clinical characteristics and the dynamic changes of myocardial enzymes in patients with severe/critical coronavirus disease 2019 (COVID-19) with cardiac injury. Methods A total of 18 severe/critical COVID-19 patients in our hospital from January 7,0 to March 1,0 were retrospectively analyzed. According to the detection value of cardiac enzyme or troponin I during hospitalization, patients in the normal range were classified as nonmyocardial injury group (n＝13), and patients with abnormal elevation were classified as myocardial injury group (n＝5). The epidemiological and clinical data of the two groups after admission were compared and analyzed, and laboratory indicators such as blood routine, liver and kidney function, myocardial enzyme, C-reactive protein were analyzed, and the changes of creatine kinase, creatine kinase isoenzyme MB, N-terminal pro-brain natriuretic peptide (NT-proBNP) and troponin I were dynamically analyzed. Results Of the 18 severe/critical type patients, 27.8% (5/18) had myocardial injury. Compared with the nonmyocardial injury patients, there were no significant differences in age, gender, basic diseases, symptoms and signs, time from onset to hospitalization, body temperature, heart rate, diastolic blood pressure and hospital stay in the myocardial injury group, but the systolic blood pressure in the myocardial injury group was significantly higher than that in the nonmyocardial injury group(P＝0.017 1). There was no significant difference in white blood cell count, neutrocyte count, lymphocyte count and mononuclear cell count between the two groups upon admission. Similarly, there was no significant difference between the two groups in alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, α-hydroxybutyrate dehydrogenase, creatine kinase, creatine kinase isoenzyme MB, blood urea nitrogen, serum creatinine, C-reactive protein and NT-proBNP. Dynamic analysis found that in patients with myocardial injury, creatine kinase, creatine kinase muscle-brain isoenzyme, troponin I, and NT-proBNP gradually increased during the 4～5 days of hospitalization, and gradually returned to normal after 9～11 days. Conclusions Higher systolic blood pressure in patients with severe/critical COVID-19 may be associated with higher risk of heart injury.Abnormalities in myocardial enzyme spectrum occur in the early stage of hospitalization. Early detection and intervention are beneficial to the prognosis of patients with heart injury.