Abstract: Talc is a magnesium−containing silicate mineral, which is often associated with metal sulfide ore. In the flotation of sulfide ore, talc often floats into the concentrate due to its excellent natural floatability, resulting in excessive magnesium content in the concentrate, thus affecting the subsequent smelting. Organic reagents are of common talc depressants, which have the outstanding depressant effects on the talc. Therefore, the depressant mechanism and research progress of organic depressants on talc in the flotation process of sulfide ore were comprehensively summarized. It was pointed out that these depressants mainly form hydrogen bonds, chemical interactions or hydrophobic interactions between hydroxyl groups, carboxyl groups, or hydrophobic hydrocarbon chains in the molecules and oxygen atoms, metal ions or hydrophobic points on the surface of talc. Therefore, they were adsorbed on the talc surface, to reduce the hydrophobicity of talc surface, and realize the depressant for talc.