Abstract: Objective To understand the immune effects of recombinant yeast hepatitis B vaccine (RYHBV) on human population. Methods: During 1997-2002, the inoculation of RYHBV was implemented among the vulnerable population on the basis of HBV infection index testing. In 2003, 5 groups of research population were obtained using cluster random sampling for the tests of common condition and HBV infection index to determine the immune effects of RYHBV based on different ages and inoculation times. Results: The HBsAg nati-HBc positive ratios of different age groups inoculated with RYHBV were remarkably lower than those of non-inocluated,and the anti-HBs ratio was apparently higher. The immune effects was better in population aged <45 years with anti-HBs positive ratio of more than 76.29%. Within 1-5 years after im-munity,the HBsAg positive ratio remained below 1%, and the anti-HBs positive ratio above 77.66%. Dif-ferent inoculation times resulted in different efficacy. One time inoculation had poor effect;and two or three times inoculation had better immune effects with anti-HBs positive ratio of over 75.76%. Conclusion Good immune effects could be acchieved among vulnerable population aged<45 years with the inoculation of recombinant hepatitis B vaccine.