Abstract: Simulation analysis is made in the paper of the characteristic of the flow fields produced by and in the regions around the key components of the virtual prototype XIM-S mechanically-agitated cylindrical coal flotation machine using CFD software. Analysis shows that: the impeller works with a high pulp throughput for its high pulp suction capacity; the distribution of fluid pressure in impeller cavity is in a symmetrical but not totally balanced state; the inner side of each stator blade is found to be subjected to abrasive wear under the effect of high pressure at the point about 1/3 from the blade's top edge; the blades of the stabilizer preliminary designed are insufficiently large in height and the cutting at the back of the blades is not made in a mechanically rational manner,resulting in,therefore,an unsatisfactory flow stabilizing result; the blades of the impeller,stator and stabilizer are not corresponding with each other in number; and the flow fields of key components and in the region around then are symmetrical yet unbalanced. According to the simulation result,it is proposed to change number of the blades of stator and stabilizer all to 18 and make corresponding optimum design of these key components.