Abstract： The psychological needs and psychological problems of college students in the post-epidemic era can not be ignored. In view of the lack of family companionship for college students with left-behind experience, it is easy to produce psychological distress, and social support is beneficial to the mental health of college students. The social support and mental health of freshmen was investigated, and the influence of left-behind experience and social support on the mental health of freshmen was explored in this paper. The results show that the scores of social support (family, friends and other support) of freshmen with left-behind experience are significantly lower than those without left-behind experience, and the scores of psychological symptoms (anxiety, depression and somatization symptom) are higher. Regression analysis find that the three dimensions of social support(family, friends，and others ) of college freshmen significantly negatively predict their psychological symptoms. The simple moderation effect also find the mental health function of social support and the moderating effect of the left-behind experience. Studies have shown that the protective effect of social support on the mental health of freshmen who have stayed behind, and the optimization of social support system is an important starting point for college mental health service.

后疫情时代大学生心理需求及心理问题不容忽视。鉴于有留守经历大学生的家庭陪伴缺失、易产生心理困扰，而社会支持有利于大学生心理健康。调研大学新生的社会支持和心理健康，探索留守经历、社会支持对大学新生心理健康状况的影响。结果发现，有留守经历大学新生社会支持(家庭、朋友和其他支持)得分显著低于无留守经历者，其心理症状(焦虑、抑郁和躯体化症状)得分更高；回归分析发现大学新生社会支持三维度均显著负向预测其心理症状；简单调节效应还发现了社会支持三维度心理健康功能及留守经历的调节效应。揭示了社会支持对有留守经历大学新生的心理健康保护效应，优化大学生社会支持系统是高校心理健康服务的重要切入点。

成都工业学院课题(2023RW024);; 四川省心理学会科研规划项目(SCSXLXH2022032)