Vertically integrated anthropogenic aerosol mass concentration Ma and low-level water cloud properties (optical depth τ, effective particle radius re, and columnar droplet number Nc) were correlated over east Asia to elucidate human-induced effects on low-cloud properties. Aerosol and cloud properties were obtained from numerical simulations and satellite observations, respectively. Monthly averages of geographical matches between collocated Ma and cloud properties for three seasons showed that as Ma increased, τ and Nc increased and re, decreased, which is consistent with the Twomey effect. Their changing rates became less steep when Ma was large. However, the importance of a dynamical effect was also suggested. A comparison of different cloud top heights revealed that values of τ and re of middle and lower clouds followed those of the total water cloud cases and reflected vertical characteristics.