In order to investigate the frequency response characteristics of the main fuel control system in a certain type of aircraft engine numerical control system,a dynamic mathematical model of the components and the system was established based on force balance equations and flow continuity equations.Using small deviation linearization around the steady-state operating point,transfer functions were developed for the pressure differential module,main fuel metering module,parking control module,and the overall system.Fluent flow field simulation was employed to study the steady-state hydrodynamic characteristics and the factors that affected these characteristics of key components.Based on the results,a Simulink simulation model of the main fuel control system was established to investigate the frequency response characteristics and the natural frequencies of key flaps in depth.The results demonstrate that the frequency response characteristics of the main fuel control system are consistent with practical engineering experience and exhibit high stability margins.The natural frequency of the system corresponds closely to that of the metering valve with the lowest natural frequency in the system.When the component structure is determined,steady-state hydrodynamics have a greater influence on the natural frequency.The research results provide theoretical support for the frequency-domain optimization design of the fuel control system.