The purpose of this study was to examine the effect 8weeks core exercise gluteus maximus strengthening on body composition, basal physical fitness and balance of middle-aged women. The subjects of the study were involved in exercise group (n=10)and non-exercise group (n=10) in middle-aged women, and we carry out same inspection and measurement at before and after 8weeks gluteus maximus strengthening exercise with core exercise. List of measurement is body composition (body fat percentage, visceral fat, WHR, waist size), basic physical fitness (muscular strength, muscular endurance, muscle power, flexibility) and balance. All variable measurements are suggested in average mean (M) and standard deviation (SD), we implement Paired t-test for verification of difference in groups about before and after exercise for 8 weeks, and use two way analysis of variance (two way ANOVA) for analysis intergroup difference. All statistical significance levels are configured in .05. Like above research result, the gluteus maximus strengthening exercise with core exercise for 8 weeks implemented in the study has positive effects for change of body composition, improvement of physical fitness and balance ability (balance) of middle-aged woman, and this exercise has effect for improvement of body balance and basic stamina of middle-aged women. Besides, it can be a help to improve the quality of life of middle-aged women.