The flow filed in the jet pipe and receivers is very complicated, especially in the dynamic situation, back flow and vortex etc. exist . Based on the model of a certain jet pipe servo valve, the movement equation of valve is obtained by combining force equilibrium of spool. Applying Reynolds averaged NavierStokes equations and the standard two equation model (liquid phase), a visual simulation model of the jet pipe to receivers of jet pipe servo valve is established through fluid dynamic software FLUENT. The fluid field and transient response of the prestage are simulated and analyzed which is from jet pipe to receivers. Simulation results demonstrate that the intensity of vorticity has effects on step response of jet pipe sevo valve. The greater vorticity intensity results in the greater oscillation and the slower step response. The 45 degree is the best design of the angle between two receivers by comparing different angles between two receivers. This work has important reference value for improving dynamic response of jet pipe servo valve.