As the coal quality of raw coal fluctuates sharply in Liangshuijing Coal Mine, the raw coal sizing screen cannot meet the coal quality requirements, and the screening efficiency is low, resulting in imbalanced feeding amount of lump coal and fine coal preparation system, thus the overall coal preparation capacity declines and affects mine production in turn. The original banana screen is transformed into a double-layer screen with an ordinary fixed screen plate on the upper screen surface and a flip-flow screen plate on the lower screen surface. The transformation scheme is studied and demonstrated. The application results show that the screening efficiency of raw coal has been significantly improved after the transformation, while ensuring the screening accuracy of lump coal, thus the workload on the slime water system is reduced and the processing capacity of the coal preparation plant and the normal production of the mine are guaranteed.