Energy metabolism in patients with Hepatocellular carcinoma (HCC) accompanying by hepatitis B cirrhosis is unknown.To compare the differences in liver functions and energy metabolism between patients with hepatitis B-related cirrhosis and patients with HCC.This was a retrospective study of patients with hepatitis B-related cirrhosis (LC group, n = 75) and patients with HCC accompanying by hepatitis B cirrhosis (HCC group, n = 80) treated in Beijing You'an Hospital between January 2013 and June 2017. The resting energy expenditure (REE), respiratory quotient (RQ), carbohydrate oxidation rate (CHO%), fat oxidation rate (FAT%), and protein oxidation rate (PRO%) were measured using a metabolic cart. Liver function, renal function, blood coagulation, etc. were collected.Compared to the LC group, patients with HCC had normal metabolism, but RQ (0.83 ± 0.07 vs 0.85 ± 0.08, P = .073) and CHO% (35.5% vs 49%, P = .013) were lower and FAT% was higher (41% vs 33%, P = .030). Compared with patients with LC group, albumin (ALB), γ-glutamyltranspeptadase (GGT), alkaline phosphatase (AKP), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and prothrombin time activity (PTA) were elevated in the HCC group, while total bilirubin (TB), total bile acid (TBA), and international normalized ratio (INR) were reduced (P < .05). Cholinesterase (CHE) was positively correlated with RQ, CHO, and CHO% (P < .05), while negatively correlated with FAT and FAT% (P < .05). AKP was negatively correlated with RQ, CHO, and CHO% (P < .05), while positively correlated with FAT and FAT% (P < .05). TBA was negatively correlated with RQ and CHO (P < .05), while positively correlated with FAT (P < .05).HCC leads to increased liver synthetic function and improve the liver functions of patients with LC, at least to some extent, but the nutritional metabolism was poor.