Abstract: Objective To understand and synthetically evaluate AIDS knowledge rate of different youth groups,and to provide scientific evidence for further AIDS health education.Methods Questionnaire survey on university students,rural youth and middle school students Selected randomly was conducted using χ² test to compare the correct rate of every population,and evaluate the rate by synthetic index method.Results Except for 2 questions which were incorrect sex behavior and vertical transmission from mother to infant,the correct rate of other questions were different(P<0.05).From low to high the synthetic index of 3 group were rural youth(2.1113),university students(2.6285)and middle school students(4.1693).Conclusion ne knowledge rate of some questions among 3 groups are below the national planning standards,and the status of AIDS knowledge are different,middle school students is the highest,rural youth is lowest.Greater and targetable efforts should be made for health education to different groups.