Abstract: In order to find an outlet for the desalinized highly-mineralized mine water, an analysis is made of the contents of both cation and anion ions in such water. Based on the result of analysis, the flotation tailing water is taken as the object to explore the sedimentation effect that can be obtained by using the desalinized mine water as flocculating agent. At a proper dosage of 212 L/t of the desalinized water plus polyacrylamide, the mean settling rate can reach 5.52 mm/s with the turbidity of the supernatant being 211 NTU. The effects obtained is comparable to those when aluminium polychloride, magnesium chloride and calcium chloride are used at a respective dosage of 1950, 2683, 2970 g/t. Results of theoretical calculation and test indicate that the flocculating effect of the desalinized water is mainly attributed to the electroneutrality effect. Viewed as whole, the use of desalinized mine as flocculating agent can lead to effective reduction of consumption of commonly used agents, beneficial to improvement of economic performance of coal preparation plant. Furthermore its selective use as make-up water of coal washing system can effectively eliminate the risk posed by discharge of mine water to environmental ecology.