The invention relates to a beneficiation method for removing long quarry impurities by adopting strong magnetic flotation, comprising the steps of crushing, grinding, sieving, desliming, strong magnetically floating, floating, concentrating and dewatering. The concrete beneficiation method comprises the following steps of: breaking and grinding ore in a ball mill; grading ground minerals by a spiral grader and a hydraulic hydrocyclone twice; combining with the ball mill into a closed cycle; respectively mounting high-frequency linear vibration sieves in overflows graded twice; respectively removing impurities over 3 mm and 1 mm, such as mica, grass-roots bark, and the like; removing most of muddy substances from minerals through desliming equipment after the impurities are removed; removing mechanical iron, weakly magnetic iron ore, tourmaline and partial mica in a strong magnetic flotation machine; floating the minerals passing through the strong magnetic flotation machine again to remove residual iron minerals, mica and black minerals; and finally, concentrating and dewatering the minerals to form a product.