The invention discloses an aircraft power system average value model and large-disturbance stability domain constructing method. The method comprises the following steps: establishing an aircraft power system average value model, wherein the equivalent circuit of the aircraft power system average value model comprises a power supply, a DC-side inductor, a DC-side resistor, a diode, a DC-side filter inductor, a DC-side filter resistor, and a load which are successively connected in series to form a closed loop, wherein the load is connected in parallel with a DC-side filter capacitor; constructing a stability domain, determining the mixed potential function of the system based on the aircraft power system average value model, constructing the Lyapunov energy function of the system, and calculating the critical energy of the system in combination with amixed potential function stability theorem, and determining the stability domain of the system. The invention provides an analysis tool for the modeling and stability analysis of a multi-electric aircraft power system, and can provide an evaluation method for system parameter design and optimization, and is suitable for multi-electric aircraft power system analysis and power electronic modeling field.