Abstract: Electro-hydraulic control system has been incorporated in high power turbine-generators since early 70's,which is well known for its control accuracy and perfor-mance.In this paper,the principle and features of the first electro-hydraulic control system developed in China are described.Causes of the oscillations arising from loadfluctuations and methods to eliminate them have been explored and analysed.There dundant technigue is used to improved the system reliability.Results from long term of trial running are shown.