Purpose: explore the interaction mechanism among college students’ social support, environment, behavior and psychology, so as to provide reference for college students’ behavior guidance and mental health intervention. Methods: 2,510 college students were investigated by general situation questionnaire and college students' quality of life evaluation concise scale (QOLCS-23). Result: (1) social support has a significant positive correlation with environment, behavior and psychology; (2) behavior plays a partial mediating role between social support, environment and college students’ psychology. The mediating effect is significant, and the proportion of mediating effect is 55.22%; (3) compared with life behavior, time management contributes more to college students’ behavior ( β = 0.75, P < 0.001). Conclusion: social support and environment can directly predict the psychology of college students, and can also indirectly affect their psychology through behavior. To improve college students’ mental health level, we should pay attention to college students’ feelings and satisfaction of social support and environment, guide college students to build good behavior, especially establish the awareness of time management.