The purpose of the study was to investigate the effects of the after school sports club activity on the school life satisfaction in the middle school students. A total of 640 middle school students in D city at september, 2012 were selected using the stratified cluster random sampling method. The survey instrument was utilized for the current study. Independent variables included participation or non-participation and the level of participation(frequency, duration, intensity), and dependent variables contained the school life satisfaction(classmate, teacher, learning activity, school event, and following rules). After the pilot test, the frequency analysis, exploratory factor analysis, reliability analysis, t-test, correlation analysis, and regression analysis were conducted with the SPSS 18.0 program. Main findings were as followed: First, the school life satisfaction of the middle school students participating in the after school sports club activity was higher than it of non-participants. Second, the level of participation in the after school sports clubs activity had an influence on the school life satisfaction. In detail, satisfaction with the school life of students who frequently, long, and intensively participated in the after school sports club activity was higher.