Abstract: This study explored the aerosol distribution and vertical meteorological field characteristics during hazy days in the Sichuan Basin. The spatial distribution of AOD and meteorological conditions of two pollution weather processes from December 19^th, 2017 to January 3^rd, 2018 and from January 11^st to 24^th, 2018 were analyzed. Comprehensive analysis of MODIS MCD19A2 atmospheric aerosol optical thickness data, live lattice fusion analysis data, air quality monitoring data, and the meteorologic observation data were conducted. The results show that: (1) Chengdu was a high AOD area during the study period. (2) During the haze weather from January 11^st to 23^rd, 2018, high AOD areas were widely distributed in the Sichuan Basin. The high and low altitude circulation situation was stable, and the height of the mixing layer was low. The surface inversion and high humidity environment were conducive to the formation and persistence of haze weather. (3) During the dust weather process from December 29^th, 2017 to January 1^st, 2018, the AOD value in the Sichuan Basin showed a spatial distribution characteristic of 'high in the south and low in the north'. The dust aerosol carried by cold air moved from north to south, which caused a slight lifting effect on the mixing layer height, and the air quality is improved slightly. However, the mixing layer height was always on the low side. The dry and cold air restrained the relative humidity of the surface layer, and the local aerosol concentration decreased. In contrast, the concentration of dust aerosol particles increased with the stable surface inversion, resulting in the formation and persistence of dust weather. Our research indicated that the vertical diffusion of aerosol particles was hindered by the low mixing layer height and the stable inversion of the surface layer. Therefore, hazy weather tends to occur in winter in the Sichuan Basin.