Computer simulation of the control system for the heavy media coal washing process has been presented in the paper. The simulation model applies the Simulink module of the Matlab 5.1 software package and allows to monitor the variations of all system variables for different sets of control parameters. The densities and levels of liquids in tanks, the operation of controlled valves and liquid distributors are monitored and displayed as functions of time. The model gives a good approximation of the industrial system and allows to optimize the control algorithm and parameters of the discrete controller. The control algorithm, the block schemes of the simulation model and simulation results have been presented in the paper. Experience derived from the industrial application of computer-based heavy media control systems, designed with the use of simulation program, have also been discussed.