Based on the monitoring data from 2013 to 2018, the spatial distribution characteristics of PM2.5 in the main urban area of Chongqing were analyzed using methods such as GIS spatial center of gravity analysis. The results show that the annual average value of PM2.5 in the main urban area of Chongqing shows a downward trend year by year, with an average change rate of -11.29%, which is better than the national average level. The decline trends of PM2.5 concentration in different districts gradually converges. The daily average overwhelming rate in winter is 20.14%, and the upward trend is obvious in stages.The characteristics of the weekly cycle change are "U-shaped" and the characteristics of the daily cycle hour change are "W-shaped". The PM2.5 pollution center in the main urban area has been moving in the Jiangbei District. The overall spatial characteristics in winter are "high in the northwest, low in the southeast" and "high in the core area, and low in the suburbs".