Abstract: The trouble with the FP75150 sizing crusher of Guotoutashan Coal Preparation Plant is that it is low in efficiency and capacity and is liable to get clogged up in operation. In line with the specific plant conditions, and based on the result of analysis of the factors causing the abovementioned problems, the SSC900 sizing crusher is selected for use in place of the FP75150 version. Practice shows that the former version offers the merits of being high in crushing efficiency, capacity and operation reliability and its use has brought about a remarkable effect.