Abstract: Based on a largescale social survey， this paper discusses the impact of individuals' social networks on their mental and physical health as well as the differences in such impact on urban and rural residents. The network size was found to have a positive effect on both mental and physical health. The “core network，” characterized of higher density， lower heterogeneity， and more strong ties， affected mental health positively； whereas the opposite type of networks with lower density and weaker ties affected physical health positively. An individual's relative higher position in his/her network was related to better mental health. Finally， the impact of social networks on health was stronger in rural areas than in urban. The theoretical and policy implications of these findings are also discussed in the paper.

Key words: mental health, network status, network structure, physical health, social network