Abstract: With the ongoing development of intelligent coal preparation plants, the low-voltage power supply and distribution systems applied therein are facing a multiple of problems during this development process, such as high consumption of PLC resource, difficulties in system upgrading and maintenance, and a large number of subsystems operating with overlapping functions. To address these issues, the low-voltage power supply and distribution system used at Ningtiaota Mine′s coal preparation is upgraded with an industrial field bus-based intelligent system. The system is mainly comprised of a remote low-voltage power cut-off and supply system, a low-voltage motor protector monitoring system, an electricity quantity data collection system, and a power distribution room environment monitoring system. Functionally, it is divided into physical layer, network layer and control layer. Field application of the system shows that real-time data collection and monitoring of power supply and distribution can be effected in the power distribution room; the time required for refreshing the data relating to instruments and low-voltage integrated protection system does not exceed one second; and the plastic-cased circuit breaker′s power supply/cutoff delay time can be controlled within 3 seconds. The use of the system has led to a save of PLC resource, cut of initial capital cost, reduction of PLC′s I/O points by 5 000, a save of control cable by 30 000 meters, and decrease of background monitoring and control systems by 2 set. The upgrading practice can provide a reference for intelligent renovation of low-voltage power supply and distribution system at other plants.