Abstract: Effect of particle size on flow field distribution characteristics of solid liquid two phase flow in flotation machine is studied by using CFD fluid simulation software.Through the simulation analysis shows that discrete phase between the mineral particles and continuous liquid phase interaction is smaller,flow field distribution characteristics are basically consistent,fine particle mineral particle size on the flotation machine internal solid liquid two-phase flow characteristics has little effect.The surface pressure distribution of rotor and stator is related to the particle size,and the turbulent kinetic energy is larger in the vicinity of the region,which ensures the better dispersion of mineral particles in the region.