Abstract: In order to improve oxidized coal flotation performance, the oxidized coal of Sihe Mine is selected as the object of study. Following an analysis of the property of the coal, a study is made of the law and mechanism of the effect on oxidized coal flotation performance produced by magnetic treatment of pulp. As evidenced by test result, the magnetic treatment technology can help increase by a certain margin the yield of flotation concentrate, and at a magnetic field intensity of 0.416 T, a best flotation performance with a rise of the yield of concentrate by 2.80 percentage points can be expected. However, the mechanism of the effect of this technology still awaits further in-depth comprehensive study.