OBJECTIVE: To investigate the behavior problems of children aged 3 to 5 years in Changsha and to compare the differences of the results detected by the norm of Conners Parent Symptom Questionnaire (PSQ) in Chinese and American urban children. METHODS: A total of 854 children aged 3 to 5 years were randomly sampled from 5 districts in Changsha City and their parents completed the Conners PSQ. RESULTS: The assessment by the norm of PSQ in American urban children demonstrated that the average prevalence of behavior problems was 20.4%, with 28.1% for boys and 12.4% for girls. There were significant differences between boys and girls (P<0.01). The factor score of anxiety in girls was markedly higher than that in boys (P<0.01). Learning and psychosomatic problems were the main problems in the children. The prevalences of conduct problems and impulse-restlessness, and abnormal restlessness index detected by the norm of PSQ in Chinese urban children were higher than those detected by the American norm. The prevalences of conduct problems and psychosomatic problems in boys by the norm of PSQ in Chinese urban children were significantly lower than those detected by the American norm, while the total prevalence of behavior problems was higher than that detected by American norm. There was a poor consistency in the assessment results of most factors of the PSQ and the total prevalence of behavior problems detected by the Chinese and American norms (Kappa<0.4). CONCLUSIONS: The prevalence of behavior problems especially learning problems and psychosomatic problems in children aged 3 to 5 years is higher in Changsha. The consistency of assessment results is poor between the norms of China and America. It is recommended to use the China norm of PSQ in Chinese children aged 3 to 5 years because the Chinese norm is in line with China′s national conditions and cultural background.