Introduces the traditional fine classification equipments and compares the properties. Based on the problems of classification efficiency and processing capacity of the traditional fine classification equipment, introduces a new fine classification equipment—high efficient secondary flow classification screen. The equipment has the advantages of high efficient classification and prevents overflow from coarse particle and underflow from fine particle (with desliming and ash reduction effect) to a great extent, and without arc screen for auxiliary dewater and desliming, the underflow of high concentration and low fine content directly flows into the centrifugal machine for efficient dehydration, which creates conditions for simplifying and optimizing the dehydration process. The economic analysis shows that high efficient fine classification can create efficiency of ten million yuan or more for mining factory of the capacity of one million ton.