Abstract: : Since the traditional "PID + Proportion Servo Valve" throttle pressure control system has difficulty in precise control of the throttle pressure,a hydrodynamic throttle pressure control system has been developed based on the "PLC + High-Speed Switch Valve" hydrodynamic throttle pressure control system.On the basis of the system design,the mathematic model and transfer function of the system were built.According to the Routh Criterion that the system four order coefficient was greater than zero,through the simulation of Matlab draw system amplitude margin was greater than zero and phase margin angle greater than 45 degrees.Comparison of the measured data and the calculated data showed that the curves were similar in shape with average relative error of 4.0%,indicating the system was good in stability well and could meet the requirements of pressure control.The control system has made up for the deficiency of the existing control system to meet the "stable,fast,and provide new technical support" for accurate managed pressure drilling.