Abstract: ObjectiveTo evaluate the effect of supplementary immunization activity (SIA) of measles in Ganyu county, 2006. MethodsThe data of measles SIA in 2006 and the measles epidemic before and after measles SIA were analyzed. ResultsThe measles vaccination rate during measles SIA in Ganyu in 2006 was 96.55%，epidemiological analysis indicated that the measles specific incidence rate was 4.83/lakh one year before measles SIA and the measles specific incidence rate was 0.55/lakh one year after measles SIA, a decrease of 88.61%. The difference was highly significant (I/Isup2/sup=12.70， IP/I＜0.05). ConclusionIn order to control and eradicate measles, the priority is to insure the high coverage of measles vaccination, but the measles vaccination and management of the children in floating population, the measles surveillance and the laboratory confirmation should be improved too.