Chronic hepatitis B (CHB) is prevalent in the world, with estimated chronic carriers of 350 millions worldwide. Currently, peginterferon alfa-2a or oral nucleos(t)ides are approved for the treatment with HBeAg positive CHB, with the overall HBeAg seroconversion far from satisfactory. Therefore, efforts on the various combinations with the currently available drugs are needed to improve the overall response rates. The simultaneous combination therapy with oral nucleoside and peginterferon alfa-2a from large-scaled randomized trials did not show a superior response rate over peginterferon alfa-2a monotherapy. Recently, sequential monotherapy with lamivudine for the first 4 weeks, followed by weekly peginterferon alfa-2a has shown favorable HBeAg seroconversion rate over peginterferon alfa-2a monotherapy, based on the assumption that early viral suppression by lamivudine can restore the immune function to facilitate the later immunomodulatory response by peginterferon alfa-2a. With the recent introduction of entecavir, the more potent oral nucleoside with few drug resistance, sequential monotherapy with entecavir can potently suppress HBV DNA with 4 weeks of treatment, which may facilitate the response of peginterferon alfa-2a to achieve HBeAg seroconversion. Therefore, we aimed to conduct a placebo controlled randomized control trial to evaluate of adding entecavir early in the course of therapy can improve the treatment response.