Abstract: To investigate the feasibility of separating the pyrite from high-sulfur content refuse by gravity-fed three product dense medium cyclone,researched the characteristics of high density dense medium suspension.The result shows that the higher the density of the suspension,the better the stability,and the finer the particle size of medium solid,the better the stability of the suspension,and the viscosity is lower under high shear rate.The magnetite suspension was prepared in different density from 2.12 to 2.32 g/cm³with magnetite which grinded by ball milling for 20min,and conducted the separation test on high-sulfur refuse by gravity-fed three product dense medium cyclone at Ganbazi coal preparation plant,under the dense medium density of 2.2 g/m³,obtained the concentrate containing 30.76% pyrite,which proved that it is feasible for separation pyrite by gravity-fed three product dense medium cyclone.