Objective To know about the status behavior problems and its influencing factors of children aged 2~3 years old in Lanzhou,and promote the progress of children's psychological health. Method A total of 181 children in Lanzhou were investigated with Achenbach Child Behavior Checklist (CBCL,2~3) Chinese Version and self-made questionaire of influencing factors. Results The detecting rate of children aged 2~3 years old identified as behavior problems was 15.5%,while the rate of the abnormal for boys was 14.3% and 17.1% for girls.There was no significant difference in the factors of behavior problem between boys and girls(P＞0.05).The scores of sociality withdrawal,depression,sleeping,body discomfort,disruptive behavior,introversion and total problems were significantly higher than normal(P＜0.01),but the scores of aggressive behavior and extroversion were significantly lower than those of normal(P＜0.001).Parents' cultural level was one of the important influencing factors of the children's behavior problems. Conclusions The behavioral problems among children aged 2~3 years old in Lanzhou city are outstanding,especially sociality withdrawal and introversion.It is necessary to strengthen early comprehensive development guidance and comprehensive intervention.