Abstract: Objective The present study was conducted tO get the knowledge of the characteristics of outbreak of measles in Wanizhou District of Chongqing city in order tO find out the reasons for the disease and provide scientific basis for the control of measles．Methods Epidemiological analysis was conducted on the characteristics of epidemic outbreak of measles in Wanzhou District in 2004．Results The epidemic outbreak of measles mainly took place in rural areas and primary schools，and it was also found to take place in the urban areas districts with weak immune work．The outbreak belonged to the incidence mode of young age group．Among 158 cases，42.41％ had definite immune history．There were many infants with measles less than 8 months．Conclusion The main reasons for the outbreak were that the effective vaccination rate was low and management of immune work at basic level was not good．More attention should be paid to the immune work in key areas and key populations．