Abstract: Objective To study the cost-effect of Japanese encephalitis(JE)vaccine immunization in Jiangsu province,and provide theor etical data to adopt Japanese encephalitis vaccine immunization into China Infancy Vaccine Immunization Project.Methods Based on the JE immunization project cost and remedial expense survey in 2005 and the historical data (including JE vaccine immunization rate,incidence and mortality of JE)from the diseases sur veillance of Jiangsu Center for Diseases Control and Prevention since 1965,use cost-effect analysis to evaluate the execution of JE vaccine immunization project in Jiangsu province.Results Since 1978,JE vaccine immunization was taken in Jiangsu province,remarkable reduction of incidence rate of JE was obtained from 20.88/100 000 in 1965~1977 to 0.09/100 000 in 2005.The effect caused by avoiding JE was RMB 144 586 400,while the total cost on JE vaccine inoculation was about RMB 11 549 600.The cost-effect was 12.52:1,therefore the effect was far above the cost.Conclusion The effect of JE vaccine inoculation is prominent.The Ministry of Health of People's Republic of China(MOH)should adopt Japanese encephalitis vaccine immunization into China Infancy Vaccine Immunization Project.