To explore the relationships among social support, loneliness, self-esteem and subjective well-being, 389 college students was asked to complete the social support rating scale, the emotional and social loneliness scale, the self-esteem scale and the satisfaction with life scale. The result showed that (1) significant correlation was found between social support, loneliness, self-esteem and subjective well-being. (2) Path analysis showed a full mediation effect of loneliness and self-esteem between subjective well-being. And a significant path from social support through self-esteem and loneliness to life satisfaction suggested more complicated relations among the variables. These findings play a significant role in college students’ psychological health education.