Abstract: Aiming at the possible risks in the process of valve test, this paper describes the actuation mechanism of valves and the valve test methods for Siemens 1 000-MW steam turbines. The risks in the valve test are analyzed. From analysis, it concludes that the abnormal reduction of EH oil pressure is the most serious risk and the steam turbine will trip when the EH oil pressure drops to a certain value. Considering the possible factors that cause the EH oil pressure to drop in the valve test, the pre-control strategy is established to optimize the control logics of the control valve and is applied on the four units of HPI Yuhuan Power Plant. A case study on the abnormal reduction of EH oil pressure in the course of the valve test of steam turbine shows that the pre-control strategy that has been applied in HPI Yuhuan Power Plant is reasonable and feasible.