Abstract: A general motion model of a linear or nonlinear flexible aeroengine's rotor with unbalance multi-rigid-disk,multi-lumped-mass and multi-bearing was presented by using Lagrange's equation during any maneuvering flight and for any position of aeroengine installed in airplane.The influences of different maneuvering flights on the dynamic characteristics of an aeroengine's rotor system were discussed.It is shown that an additional damping effect,an additional stiffness effect and an additional un-periodic external exciting force acted on the aeroengine's rotor system may be introduced due to the maneuvering flight,which will great affect the dynamic characteristics of an aeroengine's rotor system,especially increasing the vibration amplitude of the aeroengine's rotor system and significantly shifting the center of motion orbit of the aeroengine's rotor system to the uncentralized position may result in the particle impact between the rotor and the stator.The influence of the maneuvering flight on the dynamic characteristics of the aeroengine's rotor system must be considered in studying the dynamic characteristics of the aeroengine's rotor system.