Abstract: Light dispersion hydrocyclones can find their wide applications in the agricultural product processing such as abstraction of edible oil, degreasing milk, concentration of fruit juice, etc. and in the process of recovery of irrigating water from town wastewater. Based on the previously developed migration probability model for single-cone light dispersion hydrocyclones, the cut size d₅₀ was theoretically predicted and correlated to the hydrocyclone number. The results can be used to compare the separating capacities of different hydrocyclones with different structural parameters under different split ratios, flow rates and fluid properties. It is indicated that the split ratio has a relative small effect on the cutting size while the semi cone angle and sizes of overflow and underflow orifices have very large effects. The hydrocyclone radius R₀, the flow rate and the fluid properties affect the cut size d₅₀ in such a way that the hydrocyclone number will keep constant when these parameters vary. The separating capacity of a hydrocyclone will increase with decreasing R₀ as the cut size is proportional to the square root of R₀.