Objective To investigate the clinical significance of high mobility group box-1 protein (HMGB1) in chronic,severe hepatitis B patients and liver cirrhosis.Methods The contents of HMGB1 was measured by enzyme-linked immunoassay (ELISA) in the patients (include 40 patients with chronic hepatitis B and 18 severe hepatitis B patients and 18 liver cirrhosis patients) and 20 health controls.The levels of relative biochemical indicators,prothrombin time activity percentage (PTA) and the hepatic fibrosis were determined by biochemical methods.Results The contents of HMGB1 was significantly increased in severe hepatitis patients in comparison with that in chronic hepatitis B patients(P ＜0.01).The contents of HMGB1 in the chronic hepatitis were significantly increased in health controls(P ＜0.01).The contents of HMGB1 had significant difference among the liver cirrhosis patients,the severe hepatitis patients and the chronic hepatitis(P ＜0.01).There was positive correlation among the contents of HMGB1 and total bilirubin (TBIL),the proportionality of aspartate aminotransferase and alanine aminotransferase (AST/ALT),hyaluronic acid (HA) and procollagen Ⅲ N-terminal peptide (P Ⅲ NP) (r = 0.865,0.646,0.783,0.662,P ＜ 0.01).There was negative correlation among the contents of HMGB1 and prothrombin time activity percentage (PTA) and albumin (ALB) (r =-0.915,-0.852,P ＜0.01).Conclusion The contents of serum HMGB1 were closely associated with disease severity in chronic hepatitis B patients.HMGB1 was an index to auxiliary diagnosis hepatic fibrosis.