Objective：To detect and identify differentially expressed proteins in the sera of patients with HBV-related primary hepatic carcinoma and discuss their possible role in early diagnosis of primary hepatic carcinoma.Methods: The surface-enhanced laser desorption/ionization time-of-flight mass spectroscopy (SELDI-TOF-MS) was used to screen for the differentially expressed serum proteins in patients with HBV-related primary hepatic carcinoma,liver cirrhosis,chronic hepatitis,and healthy adults.Then the most differential protein sample was isolated and purified by ionic exchange chromatography and was subjected to mass spectrometry analysis.The screening results were used to establish a diagnosis model for hepatic carcinoma and the accuracy and sensitivity of the model were assessed.Results: CM10（weak cation exchange）chip found 44 differentially expressed protein peaks (P<0.05) in hepatic carcinoma group compared with those in the healthy adult group,with 21 up-regulated and 23 down-regulated.Fifty-one differential peaks were identified in hepatic carcinoma group compared with those in the liver cirrhosis group (P<0.05), with 47 up-regulated and 4 down-regulated.The expression of protein with a mass-to-charge ratio (m/z) of 5 805 gradually increased in order in the healthy adult, chronic hepatitis, liver cirrhosis and hepatic carcinoma patients; and the expression in hepatic carcinoma group was significantly higher than that in the healthy adult group (P＜0.01); peptide mass fingerprint (PMF) after enzyme hydrolysis showed that 2 of the peptides were partially identical to chondroitin sulfate synthase 2.A diagnosis model of hepatic carcinoma was successfully established based on the differentially expressed proteins,with an accuracy of 94.82％( \[23+32\]/58 ),a sensitivity of 88.46%（23/26），and a specificity of 100%（32/32）.Conclusion: We have successfully screened out the differentially expressed proteins in the sera of patients with HBV-related primary hepatic carcinoma; the most differentially expressed protein (5 805) has 2 peptides partially identical to chondroitin sulfate synthase 2 in sequence.The established model may help to diagnose HBV-related primary hepatic carcinoma.