This kit is used for the qualitative determination of HBeAg in human serum or plasma. Hepatitis B e antigen (HBeAg) appears at the same time or after the infection of hepatitis B virus, and the peak of HBsAg in blood is also the peak of HBeAg. HBeAg positive showed that HBV replication was active and infectious in vivo. HBeAg could be turned negative before HBsAg turned negative. If HBeAg continues to be positive, it can develop chronic persistent hepatitis B virus infection. It can not be used as the only index for the evaluation of patients' condition, but also for the comprehensive analysis of patients' clinical performance and other laboratory tests.