Abstract: In this paper, the spatial distribution and temporal change characteristics of aerosol optical thickness in Southwest China from 2001 to 2016 are analyzed by using MODIS aerosol optical thickness products formed by NASA. The results show that: (1)The performance of spatial distribution characteristics of annual average aerosol optical thickness is showed that aerosol optical thickness is higher in the east than in the west, and the aerosol optical thickness in low altitude is higher than that in the high altitude. The high value center is located in the southern part of the Sichuan basin, and the low value area is located in the western plateau and northern part of Yunnan. (2) The seasonal spatial distribution characteristics of aerosol optical thickness is similar to the annual characteristic. (3) In Southwest China, the aerosol optical thickness in Chongqing is the largest, followed by the Sichuan basin and Guizhou, and again in Yunnan. The aerosol optical thickness is the smallest in the western Plateau. (4) In Southwest China, from 2001 to 2016, the annual aerosol optical thickness shows a significant decrease trend. The variation of aerosol optical thickness in summer and autumn greatly, and the aerosol optical thickness in summer and autumn show significant reduction trends.