Interstitial fluid between two approaching particles will give rise to an energy dissipation in the process of their collision due to the viscous effect. Compared with gas-solid fluidized bed, particles in the liquid-solid fluidized bed will generate more energy dissipation due to the viscosity of liquid being much higher than that of the gas. In the present study, the Discrete Element Method (DEM) was employed to simulate the hydrodynamics of the particle flow in a liquid fluidized bed. The interstitial fluid effect was taken into account by incorporating a dynamic coefficient of restitution for colliding particles into the damping coefficient. Probability distribution of particle velocity gradient was analyzed with variation of superficial liquid velocity for particles with different diameters. Effect of fluid properties on particle flow hydrodynamics was also studied. Simulated results show that particle velocity gradient and granular temperature are clearly affected when a dynamic coefficient of restitution is employed and the effects of interstitial fluid on the hydrodynamics of wet particle fluidization should be considered in numerical simulations. Simulated particle pressure agrees well with experimental data in the literature. (C) 2017 Published by Elsevier B.V.