Abstract: In view of problems of too many connections, long distance, poor reliability and many fault points of PLC control system for coal blending used in coal cleaning plant, the paper proposed a reform scheme of coal blending control system based on Profibus-DP fieldbus, and introduced the system topological structure, reform methods of data upload of weighing controller and frequency converter communication, hardware parameter settings and configuration. The actual application showed that the system runs stably, improves quality of coal blending and reduces failure rate with good maintainability.