Abstract: Objective To analyze the effect of enhanced immunization for school age children in Hongkou District of Shanghai in immunology and epidemiology. Methods One month after completing immunization, the blood antibody titers were measured by ELISA method, and compared with the those of non enhanced immunization, for epidemiological survey were collected history of measles immunization and close contact with the measles. Results It could not be thought that strengthening immunization improved antibody positivity rate,the protection rate, and geometric antibody average concentrations. There was not statistical difference in antibody levels between measles vaccination 2 times and 3-4 times.Conclusion In the regions where routine immunization rates reach a high level, strengthening immunization done on large scale is a waste of vaccine resources, human resources and financial resources, and leak re-vaccination should be done as a cost-effective preventive measure.