Abstract: In order to study dynamic response characteristic of hydraulic propeller control system for a work-class ROV(remotely operated vehicle),a dynamic system model for hydraulic thruster controlled by a servo valve was constructed with respect to propeller dynamic load characteristics. A solution method for motor flow,motor pressure,motor speed,propeller torque and thruster was presented. The dynamic response characteristics of hydraulic propeller control system with different step control voltages were analyzed by numerical simulation,constructing a thrust constraint model in thrust allocation and obtaining the nonlinear function relationship between the control voltage and the expected thrust. Compared with tank test results of hydraulic propeller,the simulation results show the model is accurate and reliable for the analysis of motion control,thrust allocation and hydraulic propeller control of underwater vehicles and dynamic positioning ships.