Objective To explore clinical significance of Pre-S2 antigen in inapparent and apparent hepatitis B virus infections.Methods Pre-S2 antigen and HBV serum markers of inapparent and apparent hepatitis B virus infection cases were detected by enzyme linked immunosorbent assay.Results In cases with inapparent hepatitis B virus infection,co-positive rate of Pre-S2 antigen and HBeAg was 93.10%,and of Pre-S2 antigen and HBeAb was 60.00%.The positive rates of Pre-S2 antigen in people with positive HBsAg,HBcAB and people with positive HBsAg,HBeAb,HBcAg were 92.31% and 62.50%,respectively.While the positive rates of Pre-S2 antigen in acute and chronic hepatitis B patients were 90.91% and 61.54% respectively.Conclusion Pre-S2 antigen has great significance in detection of mutation and serum infection ability of hepatitis B virus infection cases(especially in inapparent infection cases).Meanwhile,it also has obvious significance in judging changing and clinical outcomes of inapparent hepatitis B patients.