Children with autistic spectrum disorders (ASD) are diagnosed by deficits in social interaction and linguistic skills, and restricted interests and stereotypic pattern of behavior. They have difficulties in motor, perceptual, cognitive, linguistic functions. In the present article, we proposed the comprehensive view point for understanding children with ASD; Relationships between various psychological functions, interaction between individual and environment, developmental mechanisms and developmental change by the appropriate intervention. We first described the profiles of ASD, prevalence, diagnostic criteria and resent assessment measures with the possibilities for very earlier screening in one year. Recent advancement of early intervention studies and the guideline for the application showed that early intensive treatment, pivotal behavior treatment, structured environment and parent-support program were effective for promoting the development of children with ASD. The developmental mechanism and treatment curriculum were analyzed in positive social interaction, joint attention, imitation, auditory comprehension, vocal production, verbal behavior and conversation. Children with high-functioning autism and Asperger syndrome have deficits in understanding ambiguous context, higher-ordered linguistic rules, social interaction and other's “mind”. We reviewed the treatment studies for these difficulties and found that the effective treatment included the “visualized” procedures, because children with ASD have “strength” in visual thinking. Video modeling and in-vivo role playing were effective for generalizing the acquired social skills to everyday life situation. We, as scientist ⁄ practitioner, discussed the future direction of evidence-based studies for developing children with ASD.