Abstract: On the basis of the computational fluid dynamics (CFD) method and the model of Euler two-phase flow, a numerical simulation was developed for the mixing process of two-phase flow of solid-liquid in vessels. The distribution of solid-liquid two-phase flow at different rotation speeds was investigated, yielding the critical rotation speed that makes all the solids be suspended from the bottom. The results showed that the central depositional area was gradually decreased with increasing the rotation speed. For the flat blade turbine agitator, when the rotation speed was increased to be higher than 300 r/min, all the solids were suspended from the bottom. The critical rotation speed was only 250 r/min for the pitched turbine type agitator. In case the installation position was changed, both the two types of agitator can make all the solid particles be suspended from the bottom at a lower rotation speed. We subsequently performed experiments on the mixing of water and silver sand. On the basis of these experiments, the critical rotation speed and the rotation torque were obtained. These results clearly showed that the numerical simulation results were validated by the mixing experiments. Besides, by changing the angle of the blades and the installation position, the mixing experiments and the numerical simulations showed well consistent. It was demonstrated that the pitched turbine type agitator was more suitable for the two-phase mixing of solid-liquid flow. The solid particles can suspend at a lower critical rotation speed in case the installation height is 0.5~0.8 times higher than the diameter of agitator, which can remarkably reduce the mixing power and achieve more economic benefits.