Abstract: On the basis of analyzing the existing problems of coal mine power supply protection, combined with the development trend of coal mine power supply systems, it proposed power supply protection system based on digitized power network. The system built the communication model in accordance with the standard of IEC61850, it could collect synchronous data of the whole network in real-time. On this basis, it determined the fault region by using the area differential protection method. At the same time, through communication model, this system controlled lockout information uniformly, it could cut off the fault region to prevent the grade trip. The field test had proved the superior performance of this system.