Abstract: In order to facilitate design calculation and model selection of fine coal heavy medium cyclone, the equations expressing the relationship between cyclone diameter and cyclone capacity and working pressure are derived. The corresponding linear regression equation is obtained through fitting of the design parameters of the heavy medium cyclones commonly used domestically for treating fine sized coal, for verifying the correctness of the cyclone diameter-capacity relationship equation, and derivation of the constant terms of the expression of cyclone diameter-working pressure relation. The expression of cyclone diameter-working pressure is verified through industrial test. Study shows that: the result calculated using the diameter-capacity expression is basically the same as that calculated with the fitted linear regression equation, which can yield a better result when used for prediction of cyclone capacity; under testing conditions, an improved cyclone separating performance can be achieved through adjusting feed inlet pressure based on calculation data; and the result of study may serve as a basis for design calculation and model selection of fine coal heavy medium cyclone.