Abstract: Objective To examine the prevalence of autism in 2-6 years old children in Yunyan district of Guiyang city.Methods Using completely random cluster sampling method,we chose 12 from 60 kindergartens in Yunyan district and 3 211 young children aged 2-6 years were seleted from the kindergartens.Clancy Autism Behavior Scale(CABS)was used for screening and the suspected autism children with CABS scores of ≥7 were diagnosed according to the criteria of Diagnostic and Statistical Manual of Mental Disorder(4th ed.)(DSM-Ⅳ)by two pediatric neurologists.Results The total number of the children surveyed was 3 211(1 741 males and 1 470 females).Totally 7 male autism cases were diagnosed,with a prevalence of 21.80/10 000.The age of the cases ranged from 3.34 to 4.78 years,with an average age of 4.12±0.62 years.There were no differences in the prevalenc rate of autism between the children of different age(χ²=0.06,P=0.814).And the prevalence rate of autism was 19.96/10 000 for the Han nationality and 28.32/10 000 for ethnic minorities,without significant difference between the two groups(χ²=0.18,P=0.67).Conclusion There is a high prevalence rate of autism among 2-6 years old children in Yunyan district of Guiyang city and the prevalence rate is higher in the males than in the females.