Abstract: The trouble faced by Daizhuang Coal Preparation Plant is that the clean coal is low in yield rate and high in moisture due to deterioration of raw coal property and use of outdated coal washing processes. To deal with this situation, an analysis is made of the main problems of the primary jigging washing system and the coarse slime recovery system. To adapt to the variation of raw coal property, the plant's primary jiggng washing system is renovated by shifting to the use of heavy medium separation system, and the coarse slime is separated and recovered using compound vibrating screen plus dewatering centrifuge. Practice over nearly one year shows that the use of the renovated washing system can operate with the desired result and remarkable economic benefits as evidenced by the rise of yield of clean coal by 5 percentage points and drop of moisture of clean coal by around 1 percentage point.