Abstract: Objective:Evaluation on the antibody reaction and epidemiol-ogy effect of type I inactivated vaccine againsthemorrhagic fever with renal syndrome (HFRS).Materials and Methods:After fel-lowing up 48 months of a randomized controlled field trial of type I inactivated vaccine against HFRS.indirect immuno fluorescent method(IFA) and Mcro-CEP method (MCPENT) were used in testing the titer of IgG and neutralizing antibody in series sera of IFA negative antibody before vaccine given respectively;Epidemiology effect of type I inactivated vaccine against HFRS was studied.Results The side effects of vaccine was 3.78%.The sera con-version rate of IFA and MCPENT after two weeks of vaccine given before booster> after two weeks> two years and three years of booster were 65.6% and 50.0%.and 3.8%.and 0.0%.and 83.3%.and 75.0%.and 16.7%.and 6.7%.and 12.0% and 4.0% respectively;also the GMT of that IFA and MCPENT were 13.3 and 3.9.5.1 and 25.14.1 and 4.9,1.7 and 1.1.and 1.3 and 1.1 respectively.After fellowing up 48 months no HFRS case was found among the vaccinees who received the whold schedule vaccinations while 15 and 20 HFRS case were confirmed in the control group matched to the whole schedule vaccinees and in the other group of vaccinees no given respdectively.The protective efficacy of the tested vaccine was 100%.There were 23 and 10 HFRS cases of type I and H-2 HFRS cases of on type.Conclusion:The middle-term of epidemiology effect of type I inactivated vaccine against HFRS was good and antibody level of vaccine induced droped more after four years.The randomized controlled fields of type I inactivated vaccine against HFRS should be continued to fellow up so as to received long-term epidemiology effect of the vaccine.