Mental health problems among college students have become increasingly prominent, and the traditional school-centered mental health education model can no longer meet the diverse psychological needs of students. The university-family-society collaborative mechanism is of great significance for integrating multi-party resources and improving the effectiveness of mental health education. At present, university-family-society collaboration is faced with practical dilemmas such as insufficient conceptual understanding, poor linkage effects, unbalanced goals, and lack of quality evaluation. Based on the ecosystem theory, the construction of the collaborative mechanism should follow the following paths: deepening the recognition of collaborative concepts, strengthening collaborative linkage effects, scientifically formulating collaborative goals, optimizing collaborative quality evaluation, consolidating the dominant position of schools in education, guiding families to exert their cornerstone functions, and activating the supportive role of society. By constructing an institutionalized, standardized, and long-term university-family-society collaborative mechanism, an all-round mental health support network can be formed to promote the mental health development of college students.