This study aimed to explore the relationship between poverty and children’s mental health in the social context of China. Data were consisted of 1314 children, which were collected with a multi-stage cluster random sampling method in Xiushui, a typical poverty city in China. Structural equation modeling was adopted to test the hypothesized model. Results showed that both social causation model and social selection model could explain the relationship between poverty and children’s mental health in Mainland China. The implications of these findings on theory and social work services were also discussed.