Abstract: Using the 2010 and 2014 China Family Dynamics Tracking Survey(CFPS)data and based on quasi-natural experiments in the winter central heating policy in northern China, this paper estimated the impact of air pollution on the mental health of Chinese residents using Regression Discontinuity. It was found that:(1)Air pollution has a significant negative effect on the mental health of residents. The same conclusion was reached even though the air pollution index was changed and four different pollutants were studied.(2)The negative effect of air pollution on mental health is heterogeneous for different groups of people, especially for non-provincial urban residents, lower-educated residents and women.(3)Through the analysis of the depressive symptoms of the CES-D scale, it is found that air pollution is more likely to cause people to feel depressed, indicating that air pollution can not only affect people's mental state by damaging the health of the body but also damage an individual's mental health by directly affecting their emotions, causing anxiety, uneasiness and other negative emotions.