<p>Pump reversal as a turbine has become an effective way to recover surplus liquid energy at present. In this paper, to study the influence of solid particles in the incoming medium on pump as turbine, based on mixture model, the full three-dimensional internal flow of a single stage and suction centrifugal pump reversed as turbine was numerically calculated, and the effects of three typical particle properties (density, concentration, and diameter) on the key performance parameters, including hydraulic turbine head, energy recovery efficiency, and radial force, were obtained under the rated working condition. The results show that the axial force on the pump as turbine impeller under solid–liquid two-phase flow increases and the radial force decreases compared to the single-phase clear-water flow. Each external characteristic parameter shows a different trend with each particle property changes. The axial force increases with the density, concentration, and diameter of particles. Under low particle density, low concentration, and small particle size, the radial force acting on impeller is smaller.</p>