In this study, a four-season field campaign was conducted from December 2017 to November 2018 for the study of aerosol optical properties in the northern suburbs of Nanjing. The aerosol absorption and scattering coefficients during the observation period were from high to low in winter, spring, fall, and summer, respectively, with bimodal daily variations, and the early peak time of absorption coefficients was early in summer and late in winter, which was due to the changes in the boundary layer heights and the timing of human production activities in different seasons. The average AAE was higher in summer and fall, indicating that brown carbon contributed more significantly to aerosol uptake, while black carbon uptake dominated in spring and winter.SAE was higher in spring and winter than in summer and fall, and both aerosols were dominated by fine modes, with smaller aerosol particle sizes in spring and winter. Aerosol optical properties are influenced by meteorological conditions and chemical components. The transport of pollutants under the influence of the northwest monsoon leads to high values of aerosol extinction coefficients during the fall and winter seasons when the wind is from the northwest. Local pollutants in the direction of east and southeast winds spread to the observation site with wind in spring and summer seasons, resulting in high values of aerosol extinction coefficients. The high aerosol extinction coefficients at both low and high wind speeds during the fall and winter seasons may be attributed to the accumulation of pollutants due to poor diffusion conditions at low wind speeds and the long-range transport of pollutants at high wind speeds. Aerosol extinction coefficients at the observation sites increase rapidly when air masses from inland are transported to the sites, and decrease when air masses from the sea are transported to the sites. When the relative humidity is less than 90%, the aerosol extinction coefficient is inversely proportional to the visibility, while when the relative humidity is more than 90%, the visibility is generally less than 10km, and the relationship with the extinction coefficient is not significant. The water-soluble ions in the PM2.5 components in the spring and winter seasons are mainly secondary source ions, and the correlation between aerosol extinction coefficients and nitrate ions is higher than that of sulfate ions, and pollutants affecting the aerosol extinction coefficients mainly come from transportation sources. In contrast, pollutants affecting aerosol extinction coefficients in summer and fall were mainly from stationary sources such as coal combustion. The contribution of brown carbon to the absorption coefficients was greater in summer than in fall, probably due to the increase in black carbon emissions in fall, which increased its light absorption contribution, and the relative decrease in the light absorption contribution of brown carbon.