Objectives：To explore psychological and behavior patterns of children with malignant tumor at various ages as well as their influencing factors in order to provide references for clinic treatment. Methods：Totally 120 children with malignant tumor were in－vestigated with Rutter behavior questionnaire. Together with clinic examination and intensive talks，the major influencing factors were clarified. Results：Among the 120 children，detection rate of behavior problem was significantly higher in 54.6% aged under three，61.5% aged between four to seven，24.3 aged between eight to fourteen than in control group（10.7%），with statistical significances（P＜0.01）. Conclusions：Major influencing factors for behavior problems of children with malignant tumor include education methods of parents，family intimacy，responses of both children and parents to tumors，selection of care-taker. Besides，individual psychological and physical treatment should be provided to enhance their responding ability and cultivate their characteristics，ultimately promote their sound development.