Abstract: Given the demands for carrying out both intensified and green mining, high-efficiency conversion and clean utilization of coal, the proportion of raw coal treated has been seen to keep rising. Meanwhile, the high-efficiency classification and thickening of fine coal in slurry water has gradually become a process link attracting the attention of every coal preparation plant. Hydrocyclone as a key equipment for making high-efficiency classification and thickening of coal slime has found widespread application in slurry water treatment system of coal cleaning plant. The paper introduces the structure and working principle of hydrocyclone, and presents a summary of the progress of the research work on hydrocyclone′s cylindrical, conical, feed inlet, overflow and underflow parts. Finally, the co-authors point out the trend of development of hydrocyclone is toward making it intelligentized, diversified in structure, polarized in size, and diversed in manufacture materials. The study made herein provides a reference for hydrocyclone design and application in the future.