In view of problem existed in SCADA-EMS power dispatching system of coal mine that time between master station and RTU of remote substation can not synchronization to influence accuracy of collected data, the paper proposed a design scheme of SCADA-EMS power dispatching system of coal mine based on GPS. The system real-timely monitors operation condition of power system through SCADA-EMS and can make remote access through client, and uses method combining GPS with PLL to realize real-time performance and accuracy of collected AC data of RTU. The actual application showed that the system can ensure stable operation of power system of coal mine effectively.