Objective:To investigate the early behavioral characteristics of children with autism within the age of 1.5 to 3 years in order to provide basis for early diagnosis and intervention. Methods: Using mass random sampling, 8006 children aged 1.5 to 3 years in nine districts in Tianjin were screened with a self-made questionnaire. Totally 432 children with suspected autism were diagnosed and rated according to the diagnosing criteria of DSM-Ⅳ and assessed with the Childhood Autism Rating Scale (CARS). Their behavioral characteristics were assessed with the Autism Behavior Checklist (ABC) and the early behaviors were compared between the children with autism and the normal children. Results: Children with autism in infants and suspicious positive group were different from normal children in 9 items such as" Abnormal language skills", "No index points the light", "No acts of posing as the game", "Could not normally play with toys, "and others(P <0.05). Children with autism in infants were different from suspicious positive group in 5 items such as"Children have no eye contact with others". The items with positive rate higher than 95% were interpersonal communicate barriers, mimic the functional deficiencies, language communicate barriers, non-verbal communication barriers and mental deficiency in CARS. The results of ABC showed that severe autism had much higher scores than mild to moderate autism both in the sense (S) and body function(B) areas [(8.00 ±3.30) vs. (5.15 ±2.58), (12.00 ±6.12) vs. (6.15 ±3.26); Ps <0.05]. Conclusion: The develop mental and behavioral symptoms can exist in early period of life of children with alltism, to which highly attention should be paid.