Abstract: The sedimentation properties of tailings out of immersed gold beneficiation are studied in the medium of water.The influence of sedimentation properties by the change of molecular in the following three circumstances, cation flocculent, anion flocculent and with no ion flucculent, over the settling performance is also studied.The result shows that the flocculating effect of anion poly-acrylamide for fine tailings is the best, and that of cation poly-acrylamide and with no ion poly-acrylamide is less favorable.The best amount of anion poly-acrylamide reagent is 20 g/t.