The present invention relates to a method for fining powders and an apparatus employing the same. By fast rotating the collision plates in a chamber, the powders can be continuously pulverized at high velocity. The chamber is maintained in a stable low pressure, so that gas flows are generated by planes of the rotating collision plates and the powders can be sorted. The present invention can perform functions of both pulverizing powders of D50<20 .mu.m to D50<2.0 .mu.m and sorting them with advantages of dry, low temperature, saving-energy, less consumed-material and high efficiency. The present invention is particularly suitable for oxides unable to be fined by high-temperature pyrolysis, powders having problems of changing properties at high temperature or aggregation. The present invention also provides a low-cost technology for certain powders such as cement.