Objective To explore the correlation of ABO blood group and serum cystatin C level and decompensated hepatitis B cirrhosis.Methods Retrospectively analysed the clinical data of 472 patients with decompensated hepatitis B cirrhosis,and compared with 681 healthy control volunteers.All the informations such as gender,age,family history of liver disease,hepatitis B virus infection,hepatic function classification,complications of portal hypertension and the distribution of ABO blood group were observed.Results The highest incidence of decompensated hepatitis B cirrhosis was found in A blood group.There was no significant difference in the distribution of ABO blood group for patients with different age (P ＞ 0.05).Significant correlations were observed between AB blood group and family history of hepatitis B patients,expansion of the portal veines ＞ 1.5 cm,esophageal varices,cirrhosis complications,hepatic function classification (P ＜ 0.01).C ystatin C expression was increased with hepatic function classification (P ＜ 0.05).Conclusions The risk of liver cirrhosis is increased in patients with A blood group.Compare with other blood group,patients with AB blood group has a serious progression.The level of nitrogen,creatinine,cystatin C in decompensated cirrhosis are significantly higher than healthy controls.The level of cystatin C expression is increased with hepatic function classification.Cystatin C may be a potential marker in the classification of hepatic function.