Drag force acting on particle is vital for the accurate simulations of turbulent multiphase flow, but the robust drag model is still an open issue. A hybrid parallel approach, adopting the domain decomposition method for the carrier phase and a mirror domain technique for the disperse phase, for fully resolved simulations of particle-laden flows is proposed. The code is validated by several benchmark cases, and the results show good agreement with experimental and computational data in the literature. Then, the fully resolved direct numerical simulation of particle-laden flows over sediment bed was performed to investigate the drag force on saltating particles in wall turbulence over a sediment bed. Results show that for saltating particle, the drag force along particle trajectory cannot be estimated accurately by traditional drag models originally developed for an isolate particle which depend on the particle-wall separation distance or local volume fraction in addition to the particle Reynolds number. The errors between model and direct numerical simulation(DNS) are especially clear during the descending process of particles. Through simple theoretical analysis and DNS data fitting, we present a corrected factor using the classical, particle Reynolds number dependent drag force model as the benchmark model. The new drag model, which takes the particle vertical velocity into account, can reasonably predict the mean drag force obtained by DNS along particle trajectory.