In order to apply the water hydraulic drive system to the precision die casting machine, the system with accumulator and logic valves are examined. As the pressure medium, water is environmental friendly, but it has disadvantage, e.g. leakage due to low viscosity, low lubricity and so on. In this report, the friction force acting on logic valves were taken into account in the mathematical model, because for the purpose of prevention of leakage on logic valve two or three O-ring seals were used instead of labyrinth seal used in oil hydraulic logic valve. The validity of the mathematical model is assured by experimental results. Afterward the model is introduced into the mathematical model of whole high speed cylinder drive system and characteristics of the system is examined.