The thermal dissociation of the potassium shale-potash system has been experimentally investigated. The orthogonal experiment shows that the optimum reaction temperature is 820～830℃, the mass ratio of potassium shale to potash is 1.00∶1.51, the optimum reaction time is 60min, and the particle size of the raw material is 60～80 mesh. The process was analyzed by thermal analys is of TG and DTA, and the baked materials were analyzed by X-ray diffraction. The mechanism of the reaction is proposed on the basis of the above thermal dynamic data.