Abstract: Objective To provide the reference for the diagnoisis and treatment of primary biliary cirrhosis (PBC) by studying the biochemical characteristics of PBC patients with positive anti-mitochondrial antibody M2 subtype (AMA-M2). Methods Two hundred and eighty PBC patients with positive AMA-M2 admitted to our hospital from August 2010 to March 2012 were included in this study. Their 16 serum biochemical indexes such as serum protein, lipid, bilirubin and enzymes were tested. Six kinds of serum proteins were analyzed by capillary electrophoresis. WBC, RBC, HGB, PLT and PT were calculated by photoelectric colorimetry and chromophoremetry (absorbency), respectively. Sedimentation was measured by Western method. Results Biochemical analysis showed that the percentage of abnormal serum protein and lipid (ALB, TC) was 52% and 40%, respectively. The metabolism of enzymes and bilirubin was abnormal in more than 50% of the patients. The percentage of abnormal GGT, ALP, TBA, AST, DB, CHE, LAP, ALT, and TB was 96%, 93%, 81%, 73%, 66%, 66%, 63%, 61%, 54%, respectively. The DB, GGT, and TBA were 2-fold higher than the ULN. The ALP, TB, ALT, and AST were 1-fold higher than the ULN. The LAP was 1-fold lower than the ULN.Capillary electrophoresis showed that the percentage of abnormalγ-globulin and albumin was 71% and 57%, respectively, and was l-fold lower than the ULN. The abnormal clinical hematology indicators were found in more than 50% of the patients. Tthe percentage of abnormal ESR, HGB, RBC, PT, PLT, and WBC was 84%, 49%, 46%, 44%, 41%, and 39%, respectively. The percentage of abnormal sedimentation was 84% (1-fold higher than the ULN). The percentage of abnormal RBC, HGB, and PT was ≤ 1-fold of the UNL. Conclusion Features of a variaty of biochemical indexes such as serum protein, lipid, metabolism of bilirubin and enzyme, distribution of serum protein molecules in combination of clinical hematological test contribute greatly to the clinical diagnosis of PBC.