Abstract: In order to investigate the rheological property and stability of high-density heavy medium suspension for separation of high-sulfur coal refuse, and determine the most appropriate technological process parameters, a systematic study is made of the high-density medium suspension having a density of 1.8-2.3 g/cm³ and a content of nonmagnetic materials in a range of 10%-35%. Study result indicates that: the rheological property and stability of the medium suspension varies in a pattern similar to that of the low-density suspension for separation of coal, namely, the higher the density of suspension, and the higher the content of nonmagnetic materials, the higher the viscosity and stability of the suspension become; and for the separation of pyrite from high-sulfur coal refuse, the density and content of nonmagnetic materials of the medium suspension prepared with magnetite powder and high-sulfur primary refuse fines should preferably be controlled within the range of 2.2 g/cm³ and 25% respectively.