The main purpose of this study was to understand relationships among the exercise behavior and middle school student’s physical self-concept. The researcher of this study applied questionnaires survey, and referring to the documents relating to student’s exercise behavior and physical self-concept in schools and the chart of self-made "Questionnaires On exercise behavior and physical self-concept" as the resources of information. The research objects were 645 middle school students in Taichung. The data was analyzed through the methods of Pearson’s product moment correlation, Stepwise regression. The results of the research are five factors of exercise behavior were factor of Ball Games, fitness, folklore sports, water sports, and combative sports. Physical self-concept was six factors of overall appearance, explosiveness, muscular strength, flexibility, cardio respiratory endurance, muscular endurance. Other result, the study reveals positive correlation between exercise behavior and physical self-concept. The results of this research state that different exercise behavior of middle school students indeed does influence their physical self-concept. It was suggested that future studies applying diverse physical abilities tests.