Abstract: In order to enable the industry to systematically understand the basic information of the classification equipments，the working principle and advantages and disadvantages of the spiral classifier， hydrocyclone and inclined plate classifier are mainly summarized. It is pointed out that the traditional spiral classifier has the advantages of simple structure and operation，reliable operation，stable processing capacity and classification efficiency，small transmission power，low production cost，less water content of sand return，no auxiliary equipment，easy configuration，etc.，especially suitable for one-stage closed-circuit grinding process，but there still exist the disadvantages of large volume，high price，large footprint and low classification efficiency. The hydrocyclone has the advantages of simple structure，high reliability，fine sep⁃ aration particle size，large processing capacity，no running or driving parts，high classification efficiency， adjustable operation indicators，etc.，especially suitable for the second and third stage closed-circuit grinding process，but there are many factors affecting the classification index，high requirements for stable feed volume，low grading efficiency when the feed volume is unstable，high energy consumption and production cost and so on. The main advantages of inclined plate classifier are simple structure，small footprint，high reliability，large processing capacity，no running or driving parts，high classification efficiency，low production cost，low energy consumption，no auxiliary equipment，stable feeding. The disadvantage is that the equipment height is high，and the difficulty of forming closed circuit grinding with the mill is relatively large. Finally，the situation of improved classification equipment including composite circular sieve spiral classifier，multi-stage conical spiral classifier，oblique narrow flow spiral classifier，variable diameter hydrocyclone，new heterogeneous hydrocyclone，new GTZ cyclone，CZ series high-efficiency cyclone and other improved classifiers is summarized. It is pointed out that these improved equipment generally have the advantages of higher classification efficiency，less fine underflow and coarse overflow，and wear resis⁃ tance.

Key words: spiral classifier, hydrocyclone, inclined plate classifier, classification efficiency