The purpose of this paper was to investigate the relationships among college students' life stress, self-efficacy, locus of control, and subjective well-being. A total of 279 college students participated in this study. It was administered a questionnaire consisting of questioned of concerning life stress, self-efficacy, locus of control, and subjective well-being. The correlation analysis and the analysis of mediating effect were conducted on the data. The main results of data analysis showed (1) correlations among life stress, self-efficacy, locus of control, and subjective well-being, (2) significant mediating effect of self-efficacy between life stress and subjective well-being. The direction of a further study was suggested.