OBJECTIVE: The present study investigated the behavioral patterns of autistic children during infancy to provide clues for early identification of childhood autism. METHODS: The abnormal behaviors of 30 children with autism and 26 children with other developmental disorders in infancy were investigated. RESULTS: The children with autism presented a series of abnormal behaviors, including no social smile, no eye contact and no respond to own name, and joint attention deficiency, which were distinguished from the children with other developmental disorders. The imitation and attachment behaviors were significantly different between the two groups. Repetitive motor actions and interest peculiarity were only seen in children with autism. CONCLUSIONS: The children with autism may present a series of abnormal behaviors as early as in infancy. The abnormal behaviors facilitate early diagnosis of autism.