Abstract: Based on the background of China's administrative school class system and the existing literature on peer networks and mental health, this paper proposes a theoretical presupposition on the influence of class peer networks on students' mental health and its conditional mechanism. A multi-layer linear model is applied to test this theoretical presupposition. Using the China Educational Panel Survey (CEPS) data in the years of 2014 and 2015, this study obtained the following solid and consistent findings:First, under the Chinese administrative class system, the overall mental health level of the class (social compliance effect) and the happy peer proportion (happy peer effect) can have a significant positive impact on students' mental health, and the proportion of depressed peers is significantly correlated with students' negative mental health (depressed peer effect). Secondly, students are more likely to be influenced by peers with similar mental health concepts and behaviors, and groups with poor, medium and good mental health are predominantly affected by depression peer effect, social compliance effect and happy peer effect respectively. Finally, class peer networks have a differentiated impact on the mental health of students with different group integration and parent-child communication. With the improvement of group integration and parent-child communication, the depressed peer effect gradually weakens, while the social compliance effect and happy peer effect gradually increase. In conclusion, this study tested the social compliance effect, depressive peer effect and happy peer effect under the administrative class system, and further explored the conditional mechanism of the three effects on different individual students, the relationship between individual and class, and parent-child relationship. The finding of peer effect in this paper can provide future references for the improvement of the mental health of adolescents through human intervention and adjustment.

Key words: class peer network, social compliance effect, depression peer effect, happy peer effect, mental health