Abstract: Using PM2.5 data from 1998 to 2013 that is inversed from satellite remote sensing images, and employing the methods in geospatial analysis, geographical weighted regression(GWR) and geographic detectors, this paper analyzes the relationship between urbanization and PM2.5 in ChengduChongqing urban agglomeration. The results shows as follows: (1) From 1998 to 2013, the urbanization of ChengduChongqing urban agglomeration has been rapid, and the PM2.5 average value in urban area is obviously higher than that in nonurban area, which indicates that urbanization has certain influence on PM2.5; (2) In recent 16 years, the center of gravity of PM2.5 and the city both generally move toward southeast, and their annual fluctuations in the longitude is basically opposite; (3) The nighttime light data has a good consistency with PM2.5 in the spatial distribution in ChengduChongqing urban agglomeration, and the global R2 of GWR is between 0.86-0.95. The urbanization and human activities in the study area have a significant impact on the distribution of PM2.5; (4) Geographical detection analysis shows that different urbanization factors account for PM2.5 concentration. From 2006 to 2013, the density of urban population and greening coverage of builtup areas have gradually become the main factors affecting the PM2.5 distribution in ChengduChongqing urban agglomeration.