Objective: To investigate the influencing factors of myocardial enzyme elevation after percutaneous microwave ablation (MWA) of patients with liver cancer adjacent to the heart. Methods: Eighty-three patients with liver cancer adjacent to the heart after MWA in Wuxi People’s hospital were recruited (the distance of the lesion to the heart ≤10 mm). All patients underwent creatine kinase MB (CK-MB) testing at the 24th, 48th, and 72th hours after MWA and divided into Group A (CK-MB ≤3 ng/mL, mildly elevated) and group B (CK-MB >3 ng/mL, significantly elevated) based on CK-MB value at 24 h. The data of gender, age, body mass index, hypertension, type 2 diabetes, chronic obstructive pulmonary disease (COPD), renal insufficiency, whether artificial ascites in operation, microwave-treatment time, tumor size were analyzed. Multivariate regression was performed after screening out statistically significant results. Results: The CK-MB in all patients were increased after MWA and demonstrated peak value in 30 patients of group A (65.2%) and 24 patients of group B (64.9%) at 24 h after surgery. There was no significant difference in gender, age, body mass index, hypertension, type 2 diabetes, COPD, and renal insufficiency between the 2 groups (P>0.05), while there were significant differences in the distance from the lesion to the heart, whether artificial ascites in operation, microwave-treatment time, and tumor size (P<0.05). Multiple regression analysis showed that the less distance from lesions to the heart, the long ablation time, and the big tumor size were risk factors associated with the increasing of CK-MB after MWA, while the use of artificial ascites was a protective factor. Conclusion: During WMA of liver cancer adjacent to the heart, we could minimize cardiac damage by creating artificial ascites and controlling the ablation time strictly.