Abstract: In order to determine the characteristics and flow of medium suspension and consumptions of water and medium of various related links of a heavy-medium coal separation process, the equations for calculation of required quantities of make-up thick medium, split flow and make-up water—3 requisite critical parameters for calculating medium flow of 3-product H.M.cyclone coal separation process—are derived according to the mass balance principle.The research-derived achievement enriches the theoretical system for calculation of medium flow of heavy-medium coal separation process and provides a valuable reference for optimal selection of process equipment for such a coal washing system.