A new auto-transfer system with functions of automatic transfer and overload cut in the whole power system based on the power dispatching automation system is designed and realized. This auto-transfer system consists of three parts， the power dispatching automation subsystem， the substation monitoring subsystem and the auto-transfer subsystem that jointly realize the automatic transfer function and overload cut function in the whole power system. The system can not only reduce the power network construction cost， but also enhance the reliability of power supply and ensure balanced dispatch of the power load. Actual operation results show that the system proposed is economical， simple and reliable with satisfactory operation effects.