【Abstract】 Objective To explore control efficacy of one?dose Japanese encephalitis（JE） attenuated live vaccine in 1-3 years in JE endemic areas, and provide the evidence for its control. Methods The children who only inoculated one?dose JE attenuated live vaccine from 2004 to 2006 in Guizhou were investigated, and its incidence rate within 1-3 years after inoculation was analyzed. At the same time, the immunization retrospective study to all the JE confirmed cases was done. Results The incidence rate of JE immunization county declined 62.36% compared to that of last year, but  it  rebounded  after  inoculation  for 1-2 years in some counties. Among the cases investigated, the targeted children accounted for 73.28％. No JE vaccine had been inoculated in 27 cases sampled randomly. The incidence rates of objectors were no significant difference after immunization for 1-3 years(χ2＝0.73, P＞0.05), which were 6.25/100 000, 5.77/100 000 and 4.54/100 000, respectively. The inoculation rates were 1.92% among 52 diagnosed cases, lower than that of the control(29.41%), and significant difference was found between them (χ2＝52.74, P＜0.01). Conclusion The long?term control efficacy of one dose JE attenuated live vaccine is very good after inoculation for 1-3 years , and the effective method to realize control efficacy is the increase of inoculation rate. The rebound of incidence rate was related to the actual inoculation rate in some counties after immunization for 1-2 years.