The influence coefficient method and transfer function method are applied to the dynamic balance of aero-engine flexible rotor. The static transfer function of the flexible rotor is obtained by hammering on the experimental bench of the aero-engine flexible rotor. The low-pressure rotor of CFM56-7 B engine with typical high-speed flexible rotor was selected as the research object for numerical simulation, and the transfer function of the rotor system was obtained through ANSYS harmonic response analysis. The experiment and simulation results show that the transfer function method has better balance effect than the influence coefficient method, which can effectively reduce the vibration of unbalanced rotor and avoid the disadvantage of the influence coefficient method in starting the rotor several times. It has a good application prospect in the maintenance of aero-engine.