The effect of aerosol on liquid cloud microphysical properties over the Tibetan Plateau during the warm season is investigated by employing aerosol index and cloud property parameters. Distinct differences in aerosol effect on liquid cloud microphysical properties have been found between the northern TP (NTP) and southern TP (STP). The composite liquid cloud droplet effective radius (LREF) anomalies for positive aerosol index (AI) events are positive in the NTP and negative in the STP. In both NTP and STP, when the AI anomalies are positive, the LREF anomalies are also positive, which suggests that the increased aerosol loading reduces the solar radiation reaching the ground and thus enhances the atmospheric stability, making cloud droplets not conducive to break up. This indicates that the aerosol radiative effect is not likely the reason causing the distinct differences of aerosol effects on liquid cloud properties between NTP and STP. Further analysis shows that in the STP, the LREF first increases and then decreases with the increase of AI, while in the NTP, the LREF always increases with the increase of AI, suggesting a spatial difference in aerosol microphysical effect. In the STP, the influence of aerosol on liquid clouds is mainly dependent on liquid water path (LWP) and convective available potential energy (CAPE), while in the NTP, the influence of aerosol on liquid cloud is more likely related to large aerosol particles.