The purpose of this study was to examine the effects of middle school students` participation in sports activities on school life satisfaction. The participants were 377 middle school students. The collected data were processed using the Windows SPSS 120 version statistical program for factor analysis, independent samples t-test, one-way ANOV A, Tukey`s HSD post-hoc test, reliability analysis and multiple regression analysis, and could get the result as follows: First, satisfaction with school life according to their demographic characteristics was different significantly and partially in gender, parents` income, and male students have higher satisfaction than female students, and students of big-income families have higher satisfaction than students of low-income families. Scond, satisfaction with school life was different significantly according to their participation in sports activities, and participators in sports activities have higher satisfaction than nonparticipators. Third, school life satisfaction was influenced by participation in sports activ ities as follows: co-participation had significant influence on school lessons and school regulations, and participation frequency did so on teacher relationship and peer relationship.education could newly be inserted into it.