In order to investigate the immunogenicity of the controlled-release microencapsulated hepatitis B vaccine in mice,polyethylene glycol-poly-dl-lactide (PELA) microspheres with entrapped HBsAg were prepared by double emulsion W/O/W based on solvent extraction methods. BALB/c mice were immunized with the encapsulated vaccine by oral feeding or injection. Blood samples were collected at 8 th, 10 th, 14 th and 24 th weeks, respectively, and the levels of antibody response were detected by ELISA.It was found that the scanning electron microscopy showed the prepared microspheres had smooth and spherical surface, suitable for vaccine delivery. Two groups of mice orally fed with the encapsulated or conventional recombinant vaccines, respectively, there sera showed no obvious difference in the IgG levels. At 14 th week, the group injected with a single dose of encapsulated vaccine had a similar level of IgG response to the group injected with two doses of the recombination vaccine. At 24 th week, the IgG levels of the group injected with two doses of encapsulated vaccine were higher than those of the group injected with two doses of the recombination vaccine. It concludes that Controlled-release microencapsulated hepatitis B vaccine possesses the feature of slowly releasing in vivo and long times immunogenicity. In order to investigate the immunogenicity of the controlled-release microencapsulated hepatitis B vaccine in mice, polyethylene glycol-poly-dl-lactide (PELA) microspheres with entrapped HBsAg were prepared by double emulsion W / O / W based on solvent extraction methods. / c mice were immunized with the encapsulated vaccine by oral feeding or injection. Blood samples were collected at 8 th, 10 th, 14 th and 24 th weeks, respectively, and the levels of antibody response were detected by ELISA. the scanning electron microscopy showed the prepared microspheres had smooth and spherical surfaces, suitable for vaccine delivery. Two groups of mice orally fed with the encapsulated or conventional recombinant vaccines, respectively, there sera showed no obvious difference in the IgG levels. At 14 th week , the group injected with a single dose of encapsulated vaccine had a similar level of IgG response to the group injected with two doses of the recombination vaccin e. At 24 th week, the IgG levels of the group injected with two doses of encapsulated vaccine were higher than those of the group injected with two doses of the recombination vaccine. It concludes that Controlled-release microencapsulated hepatitis B vaccine possesses the feature of slowly releasing in vivo and long times immunogenicity.