The invention relates to the technical field of aircraft power supply systems, and discloses an aircraft multi-closed loop power supply adjustment system. The system comprises multiple parallel inverter unit systems connected to a high-voltage DC power supply system and an aircraft load control system respectively. The invention also discloses an aircraft multi-closed loop power supply adjustmentmethod. The voltage inputted to a linear load system and/or a nonlinear load system is adjusted to 115 V through the multiple parallel inverter unit systems and the connected double-closed loop controller; when the linear load system is accessed, load voltage adjustment is realized through a voltage outer loop controller in the double-closed loop controller; current adjustment of the connected inverter unit system is realized through a current inner loop controller in the double-closed loop controller; through a second-order power equalization and sharing algorithm, effective sharing of the power after the linear load system is accessed can be ensured; and when the nonlinear load system is accessed, through harmonic voltage loop compensation, harmonic suppression of each frequency is realized.