The purpose of this study was to investigate the effects of body composition and health fitness of college students participated in sports activity classes on mental health. Research subjects were 109 students in ‘G’ university of Gwangju Area who have take a sports activity classes. They were divided into two types of groups; male group(n=54) and female group(n=55). Observation variable was test in one time, body composition test was body weight, lean body mass, body fat percent, waist hip ratio(WHR), and BMI. Health fitness test was muscle strength, muscle endurance, cardio-respiratory fitness, and flexibility. Mental health test was somatization, obsessive compulsive, interpersonal sensitivity, depression, anxiety, hostility, phobic anxiety, paranoia, psychoticism. Independent-samples t-test, and regression analysis were used for analyzing the data. Results found from such a comparative analysis study were as follows; Firstly, between the group of body composition and health fitness were showed statistically significant difference to the exclusion of cardio-respiratory fitness(p<.05, p<.001), between the group of mental health wasn't showed statistically significant difference. Secondly, body composition and health fitness were showed a statistically significant difference to the exclusion of body weight by pre and post test(p<.05, p<.001), mental health was showed statistically significant difference by pre and post test(p<.001). Thirdly, interaction effect of the lean body mass(p<.05), WHR(p<.05), muscle strength(p<.001), somatization(p<.05), interpersonal sensitivity(p<.05) was showed a statistically significant difference. Fourthly, body fat percent and WHR are influenced positively on mental health. However, cardio-respiratory fitness, and flexibility are influenced negatively. In conclusion, it could be to investigate the effects of body