Abstract: Due to the large particle size and complex fluid interaction, it is difficult to study the two-phase flow in multiphase pump with coarse particle. Aiming at the flow of multiphase pump with 10 mm particle size, the standard k-ω model was used to construct flow models with the same volume concentration and different particle sizes to study the influence of particle size on the hydralic characteristics of the pump and the distribution of particles with different particle sizes in the pump. Combined with the entropy production theory, the energy loss and local entropy production of the flowing parts in the pump were studied at different flow rates. The result shows that the particles accumulate at low speed at the impeller entrance in the impeller passage of the multiphase pump, and the particle velocity increases with the increase of radial distance. Between the two poles, the particle accumulation at the entrance of the second stage impeller weakens. With the decrease of particle size, the acceleration of particles in the impeller passage increases, and the velocity of particles with small particle size at the exit is larger, and the movement phenomenon of particles with small particle size sticking to the blade is obvious. Compared with the entropy production, the loss of the second stage entropy production between the poles is obviously larger, resulting in the difference in the characteristics of the two stages. Meanwhile, compared with the distribution of entropy production, the LEPR in the second stage impeller and guide blade is larger. It provides reference value for the research of the flow in the multiphase pump of coarse particles in the hydraulic lifting device of deep-sea mining and for the research and application of the solid-liquid two-phase flow of coarse particles.