Objective To study the correlation between electrocardiogram (ECG) correction of QT (QTc) interval and score of Child-Pugh in 100 patients with hepatitis B virus (HBV) infected cirrhosis, and to provide reference and basis for its application in the diagnosis of cardiomyopathy in patients with HBV infected cirrhosis. Method A total of 100 patients with HBV infected cirrhosis admitted to Hezhou People's Hospital from January 2020 to December 2021 were selected as the cirrhosis group, and 97 healthy subjects who underwent physical examination in the same period of Hezhou People's Hospital were selected as the healthy control group. All of them underwent ECG examination. According to Child-Pugh, 100 HBV-infected cirrhosis patients were divided into the group A (28 cases), the group B (40 cases) and the group C (32 cases). The general data of healthy physical examination subjects and HBV-infected cirrhosis patients with different score of Child-Pugh were collected, and the ECG QTc interval indexes of healthy physical examination subjects and HBV-infected cirrhosis patients with different score of Child-Pugh were compared. Spearman test was used to analyze the correlation between QTc interval index detected by ECG and score of Child-Pugh and laboratory index in patients with HBV-infected cirrhosis. Result The serum levels of total bilirubin (TBil), albumin (ALB), globulin (GLB) and heart rate in the healthy control group, the group A, the group B and the group C showed a gradually increasing trend, the prothrombin time (PT) showed a gradually lengthening trend, and the serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) showed a trend of first increasing, then decreasing and then increasing. Albumin/globulin (A/G) was firstly decreased and then increased, while levels of serum fasting blood glucose (FBG), 2h postmeal blood glucose (2h BG), creatine kinase (CK) and high-sensitive troponin T (hs-TnT) in the groups A, B and C showed a gradual increasing trend. The serum levels of FBG, 2h BG, CK and hs-TnT in the healthy control group were higher than those in the group B and C, and the differences were statistically significant (P<0.05). The QTc, QT interval dispersion (QTd) and corrected QT interval dispersion (QTcd) in the cirrhosis group were significantly higher than those in the healthy control group (P<0.05), and the abnormal rate of QTc in the cirrhosis group (56.00%) was significantly higher than that in the healthy control group (9.28%, P<0.05). QTc, QTd and QTcd in the groups A, B and C showed a trend of gradual extension, and the difference between groups was statistically significant (P<0.05), while the abnormal rate of QTc (21.43%, 50.00%, 93.75%) showed a trend of gradual increase, and the difference between groups was statistically significant (P<0.05). The abnormal rates of QTc, QTd, QTcd and QTc were significantly positively correlated with score of Child-Pugh in HBV-infected patients with cirrhosis (r=0.673, 0.588, 0.498, 0.529, P<0.05). Conclusion HBV-infected patients with cirrhosis had prolonged QTc, QTd and QTcd. With the increase of patient score of Child-Pugh, QTc, QTd and QTcd are prolonged, and the abnormal rate of QTc increases. The abnormal rates of QTc, QTd, QTcd and QTc were significantly positively correlated with score of Child-Pugh in HBV-infected patients with cirrhosis.