The invention discloses an ore dressing method for removing pyrrhotite from iron ore. The ore dressing method for removing the pyrrhotite from the iron ore includes that performing crushing, ore grinding, grading and low intensity magnetic separation techniques to obtain low intensity magnetic concentrate, wherein the TFE grade of the low intensity magnetic concentrate is more than or equal to 65.0%, and the low intensity magnetic concentrate comprises 0.5-1.4% of S; carrying out reverse flotation roughing and reverse flotation selection on the low intensity magnetic concentrate to obtain low-pyrite concentrate with less than 0.15% of S. Weighted by the dry ore amount for the reverse flotation, the reverse flotation roughing chemical comprises (1) pH regulating agent, to be specific, 800-1200 g / t of sulfuric acid; (2) activating agent, to be specific, 80-150 g / t of copper sulfate; (3) collecting agent, to be specific, 250-400 g / t of iso-butyl xanthate and 150-250 g / t of butyl dithiophosphate; (4) foaming agent, to be specific, 30-70 g / t of 2# oil. The ore dressing method for removing the pyrrhotite from the iron ore uses the butyl dithiophosphate and butyl xanthate or iso-butyl xanthate to form sulfur content reducing chemical mixture, the molecular arrangement between the chemical micelles is improved to form a synergistic effect, the chemical is good for mineralizing and adsorbing, the hydrophobicity and the floating speed are properly reinforced, and the sulfur content of the iron concentrate is reduced to less than or equal to 0.03-0.15%. The ore dressing method for removing the pyrrhotite from the iron ore is especially suitable for removing the pyrrhotite from the iron ore with pyrrhotite through reverse flotation.