Taking a certain lowpressure turbine electrohydraulic regulating system as an example, the coupling characteristics of its multistage amplification structure and the opening mechanism of the pilot valve port and the main valve port controlled by servo followup feedback were analyzed. The mathematical model of the system was established and simulated by using MATLAB/Simulink. The test platform for low pressure turbine electrohydraulic regulating system was built. The test results shows that the test results obtained by using the model are in good agreement with the simulation results, by which the correctness and feasibility of the mathematical model are verified. Appropriately reducing the spring stiffness of the main valve core and the effective area of the oil cylinder can significantly improve the dynamic response speed of the lowpressure and large flow system without affecting the steadystate output accuracy; by reducing the spring stiffness of the pilot valve, under the condition of constant response speed, the response time to the control oil pressure and the zero dead zone of the static output characteristic curve can be reduced; the optimal parameters which can improve the dynamic response speed of the system are proposed. The research results can provide reference for the design and optimization of the low pressure and large flow servo control system.