In this paper, we investigated the effect of liquid distribution state on size-induced granular segregation in a thin rotating drum. An image-processing method and particle-tracking technology were employed to measure the average velocity, average granular temperature, dynamic angle of repose, and intensity of segregation. Both the liquid distribution state and the rotation speed had a significant influence on size-induced segregation of wet granular materials. The rupture and formation of liquid bridges could dissipate the kinetic energy of particles, restrict the particle movement, and mitigate the size segregation behavior. The intensity of segregation decreased non-monotonically with liquid content. Moreover, the dynamic repose angle did not increase monotonically with the increasing liquid content. The results indicated that the liquid distribution state plays an important role in determining the size-induced granular segregation behavior. The relation between the granular temperature and segregation behavior is also discussed in this study. (C) 2020 Elsevier B.V. All rights reserved.