Abstract: In order to allow flocs in coal slurry water to settle with a higher dynamics, the Kaolin water containing 4% of Kaolin by weight is used as simulated coal slurry water, with is then treated through magnetic flocculation using ball-milled flyash magnetic beads as magnetic seeds and PAM and CaCl₂ as flocculant and coagulant respectively.The study is made with an aim to make known the law governing the effect on sedimentation produced by each of the 3 factors-intensity of magnetic field, proportion and size of magnetic beads used, and to determine the optimum experimental conditions.As evidenced by test result, the above-cited 3 factors all exert an sign ficant influence in this regard, and a best sedimentation result can be expected with PAM and CaCl₂ at dosages of 0.035 g/L and 0.003 mol/L respectively, an intensity of magnetic field of 196 mT, a size of magnetic particle seed of 10.66 μm and an addition of magnetic seeds of 2 g.Under the conditions as mentioned above, the sedimentation rate of flocs is 2.675 cm/g with a height of sediment of being 2.95 cm and a transmissibility of supernant reaching 93%.