Abstract: Objective To explore the clinical value of hepatitis B virus Pre-S1 antigen in the diagnosis of viral replication. Methods 450 HBsAg positive and 50 healthy control serum specimens were collected，and the Pre-S1 antigen and HBVM were detected by ELISA，HBV DNA levels by fluorescence quantitative polymerase chain reaction（FQ-PCR），and liver fuction by automatic biochemical analyzer respectively. Results The positive rates of HBeAg，Pre-S1 antigen and HBV DNA in all patients were 40.0%，57.3% and 61.6%，respectively；there were significant differences in the positive rates of Pre-S1 antigen and HBV DNA in HBeAg negative and positive group（x２=84.2，x２=110.7，P<0.01）；Pre-S1 antigen were correlated with HBeAg and HBV DNA（x２=86.5，x２=272.1，P<0.01）；AST，ALT，TBil and γ-GT in Pre-S1 antigen positive group were higher than those in negative group（P<0.01）；When serum HBV DNA was more than 2.7lg copies/ml as the cut-off value for the HBV replication，the sensitivity，specificity，accuracy，positive predictive value，positive likelihood ratio and odds ratio of Pre-S1 were 87.7%，91.3%，89.1%，94.2%，10.1 and 75.3 respectively，while those of HBeAg were 59.2%，90.8%，71.3%，91.1%，6.43 and 14.2 respectively. Conclusions Pre-S1 antigen is correlated with HBeAg and HBV DNA for HBV replication.

Key words: Hepatitis B virus, Pre-S1 antigen, HBeAg, HBV DNA