 In this cohort study, the HBeAg positive chronic hepatitis B patients would be treated with peginterferon alpha 2aPEG-IFN a-2a for 96 week and followed 24 weeks after treatment. Serum HBV DNA load, HBsAganti-HBs level, HBeAganti-HBe will be tested at enrollment and every 3 months during treatment and follow period. Parameters of liver and kidney function, and liver ultrasound examination will be tested with intervals 1-3 months. The rates of HBeAg seroconversion, HBsAg loss, and sustained viral response will be evaluated after treatment and follow up. 