A novel structure floatation cyclone with natural inlet air has been designed, and its structural characteristics and floatation principle have been analyzed. Simulations of the velocity and pressure distributions within the flow field of the floatation cyclone have been carried out using Navier Stokes equations and fluid mechanics of two-phase. Based on the flow characteristics of the coal-water slurry, reasonable boundary conditions are decided and the equations are modified, so that the final equations can describe the real flow state of the flow field of the floatation cyclone. The boundary surface position between float coal and tailings is determined and there is an air cylinder in the central region of the floatation cyclone. The research reveals the floatation mechanism of the floatation cyclone. The floatation results can be greatly improved by regulating the structural dimensions of cyclone. The experimental results show that the floatation cyclone is very effective for the floatation of fine coal grains.