Based on widely used heavy medium coal washing technology and its process, working principles and craft process of heavy medium coal washing were introduced in detail. Meanwhile, key quantities in the process as well as key parameter measurements and control principles were described. Then, data model of washing process in dense medium was set up, which was convenient to evaluate its following running state. At last, the nuclear submerged structure projection ( T - KPLS ) method was used to evaluate operation state of heavy medium coal washing in order to adjust washing process or process quantity of heavy medium.