This study investigated the density-induced granular segregation phenomenon of wet granular materials in a quasi-2D rotating drum. The motions of the granular materials were recorded using a high-speed camera. Image-processing technology and the particle-tracking method were employed to measure the intensity of segregation, repose angle, and the velocities of heavy particles. We analysed the effects of the liquid content and rotation speed on the segregation index, angle of repose, and velocity of particles in the rotating drum. The experimental results reveal that the liquid content and rotation speed have significant influences on density-induced granular segregation behavior. The intensity of segregation is mitigated with a rise in liquid content because of the stronger cohesive force between particles. We also discuss the relationship between the intensity of segregation and the repose angle.