Abstract: The hygroscopicity is one of the important physicochemical properties of aerosols, which not only affects the climate through atmospheric radiation effects, but also has an important impact on atmospheric visibility. The concepts of aerosol particle size hygroscopic growth and scattered hygroscopic growth were introduced, the methods for measuring aerosol hygroscopic growth were summarized and the effects of particle size, chemical compositions, pollution conditions and mixing state on hygroscopicity were analyzed. It was found that the hygroscopic growth of aerosols could increase the water content of particles and affect the aerosol extinction capacity, thus affecting atmospheric visibility and aerosol radiative forcing. In the future, it was recommended to focus on aerosol hygroscopic growth at high relative humidity (>95%), strengthen vertical observation research on aerosol hygroscopic growth, and widely carry out the measurement and research on aerosol scattering hygroscopic growth under both hygroscopic and dehydrated conditions.