Power accumulator and execution amplifier are the most important components of the mechanical hydraulic system of high oil pressure governor for water turbine. Optimization of the two components could improve the system reliability,reduce daily maintenance workload and cut cost. Electro-hydraulic proportional valve and digital valve are the major control valves for the mechanical hydraulic system of high oil pressure governor of water turbine with operational power equal to or less than 10 000 N·m. In the optimization design,high-speed switch valve is adopted to replace electro-hydraulic proportional valve. However,electro-hydraulic proportional valve can also be remained according to customer’s requirements. Moreover,manual valve,manual and automatic switchover valve,and hydraulic lock are substituted by hydraulic universal components which have short production cycle,low cost,and stronger versatility to meet the requirements of different customers and to improve efficiency. The optimization design is suitable for middle and small sized water turbines.