Objective:To investigate the value of arterial enhancement fraction in the diagnosis of hepatocellular carcinoma in patients with liver cirrhosis.Methods:The clinical data of 80 liver cirrhosis patients with pathologically and clinically confirmed hepatocellular carcinoma who received treatment from April 2019 to April 2021 in Benxi Central Hospital were retrospectively analyzed. The data from phase III enhanced CT scans were input into the PACS system. Two physicians independently measured the CT values of hepatocellular carcinoma and liver cirrhosis using a double blind method. The AEF values were calculated. According to Child-Pugh classification, the severity of liver disease was divided into class A ( n = 33), class B ( n = 29), and class C ( n = 18). The AEF value of hepatocellular carcinoma was compared with that of liver cirrhosis in the same group. The AEF value of liver cirrhosis was compared between different classes of liver cirrhosis. The AEF value of hepatocellular carcinoma was compared between different classes of liver cirrhosis. Results:The inter-observer agreement of mean AEF values was high ( ICC = 0.95, 95% CI = 0.93-0.97). The mean AEF value of hepatocellular carcinoma was (54.79 ± 10.95)% for patients with class A liver cirrhosis, (54.90 ± 9.99)% for patients with class B liver cirrhosis, and (54.16 ± 7.19)% for patients with class C liver cirrhosis. The mean AEF value of liver cirrhosis was (39.94 ± 6.50)% for patients with class A liver cirrhosis, (44.97 ± 4.31)% for patients with class B liver cirrhosis, and (54.11 ± 4.63)% for patients with class C liver cirrhosis. In patients with class A and class B liver cirrhosis, the AEF value of hepatocellular carcinoma was significantly higher than that of liver cirrhosis (class A: t = 5.18, P = 0.001; class B: t = 3.94, P < 0.001). There was no significant difference in the AEF value between hepatocellular carcinoma and liver cirrhosis in patients with class C liver cirrhosis ( t = 0.02, P = 0.982). Conclusion:The AEF value has an important reference value for the differential diagnosis of hepatocellular carcinoma from liver cirrhosis.