Abstract: ObjectiveTo know neutr alization antibody level ag ainst measles virus(MV)of health people in the Liaoning province.Methods693 serum samples of different age gr oups were collected in 14 counties and districts in 6 areas of the Liaoning pr ovince in 1999.Neutralization antibody was detected by cell micro culture using B95A cell.ResultsThe results indicated that positive rate was 94% in the 2~4 and 20~25 years old groups and in other groups was more than 96%,but GMT was lower in the 2~4 years old group,lowest in 6~8 and 9~11 years old groups.Which conformed to the measles incidence in 1999,the incidence was the highest in the 6~8 and 9~11 years old groups.ConclusionIt points out that children of 2 and 5 years old would be vaccinated by MV vaccine again in order to increase antibody against MV.It is best for children who are unden 14 years old being vaccinated again every 5~6 years if possiblee,because measles incidence was 0.6/100,000 in the 13~15 years old group in 1999 in Liaoning province.