Abstract: As the raw coal treated by Daichiba Plant comes from several mines, the washing system is caused to fluctuate in effects. To deal with the situation, work is made on analysis of the property of the raw coal from each mine and on comparative analysis of the alternate and mixed coal washing schemes based on the equal cut-point ash separation theory. As shown by theoretical calculation and practice, the use of the mixed coal washing scheme can lead to increase of yield of clean coal, simplification of washing process, less fluctuation of washing effects, and improvement of economic performance.