This is a study to verify effects of teaching styles and swimming activity program for an autistic child`s stereotype behaviors in swimming activities. For the purpose of this study, various types of attitude that were performed by a swimming teacher was applied. Attitudes of the swimming teacher were delinated to high-handed type and tender type. Subject of this study was an autistic child who demonstrated stereotype behaviors such as muttering, shouting, waving hand, and rolling eye-ball. The subject`s stereotype behaviors were observed during experimental study period that was constructed by 12 sessions for 4 weeks. During the experimental study period, the subject were requested to perform specific tasks that were designed by Top-Down developmental approach. The teacher also used verious kinds of reinforcement techniques without considering subject`s stereotypies. Results of this study were as follows: First, Muttering and shouting behaviors were increased by the high-handed type teaching method, and were decreased by the tender type teaching method. But Waving hand and rolling eye-ball behaviors were not influenced by any teaching methods. Second, Muttering and shouting behaviors were increased by the difficult swimming activity program and were decreased by easy swimming activity program. But Waving hand and rolling eye-ball behaviors were not influenced by any swimming activity program.