The Dense medium cyclone (DMC) is a high-tonnage device that is widely used to upgrade run-of-mine coal in coal industry. Its complicated multiphase flow structure is difficult to investigate experimentally. In recent years, Computational Fluid Dynamics (CFD) and in particular, its combination with Discrete Element Method (DEM) have been shown to be effective in overcoming this difficulty. However, such a mathematical model, particularly the CFD-DEM one, is very time-consuming in computation and not suitable for engineering application. In this paper, based on the CFD and CFD-DEM simulated data, a PC-based mathematical model is formulated to predict the performance of DMCs under various conditions. It first discusses how such a model can be developed, with its validity examined against the collected plant data. Then, the effects of some key variables related to DMC geometry, operational conditions and materials properties are examined. It is shown that the proposed model can indeed offer a convenient way to quantify the effects of different variables, being useful in the design and control of DMCs under different conditions.