The dynamics of a pilot-operated two-stage solenoid valve used in power system were studied numerically. A dynamic model coupling vibration of solenoid valve with fluid flow in the valve was derived. While solving the system equations, vibration of the valve spindle, various pressure-flow characteristics across the valve ports and orifices and pressure variation in chambers were taken into consideration. The model was validated by experimental results. The simulation results present stability of the spindle for different operating conditions and effect of working pressure and working flow rate on dynamics of the solenoid valve.