When treating the industrial waste water from metallurgical industry, applying the powde ractivated carbon together with the emulsified lime as the pre-treatment to reduce COD, the temporary hardness, and the concen tration of high valence ions in the permeate of UF.The application can effectively prolong the operation cycle of RO system.By applying the Clarifier+ValvelessFilter+PressurizedUF+Reverse O smosis technology,it is able to reduce the capital investment and the operation costs of energy consumption.