Mine drainage could be filtered and purified through goaf. This innovative technique shows merits, such as high treatment efficiency, remarkable economic benefit and extensive wastewater recycle use. However, it was detected that capacities of purifying mine drainage for goaf were decreased after a period of application. As a result, the effluent could not meet the standard of recycle water. To solve the problem, coagulant was considered to add into mine drainage reducing its high turbid degrees to certain level. After the preliminary flocculation treatment, mine drainage was piped into goaf to purify. In this way, the load of goaf was eased up. Its usage time was also prolonged. Therefore, this paper carried out the coagulation-flocculation jar test for mine drainage to discuss the flocculation parameters. By the experiment, 10 % iron trichloride is selected from four inorganic coagulants as the optimum coagulant. The optimum dose, PH value and sedimentation time are respectively 2 mL per 800 mL wastewater,6～7 and 25 min. Velocity gradient G during the process of mixing and reaction is 696 s-1 .And the value of GT is 6.264× 105. The values of G and GT will supply the basis for the design of flocculation pool in the project. The flocculation parameters will be significant for the reference of practice.