Due to the complexity of the structure and the instability of the external air flow， considerable problems inevitably occur during the operation of aero-engines. Aiming at the vibration problem of the whole aero-engine， a general dynamic model of rotor-support-casing vibration transmission is established according to the actual structure of the aero-engine and the summary of experience. Moreover， starting from the vibration control problem of the internal and external cases of the aero-engine， a novel control algorithm （geometric design method） is used to design the vibration reduction controller in the limited frequency domain. In the case of limited sensors and actuator， the controller is used to try to control the vibration of multiple outputs （i.e.， the inner and outer cases of the aero-engine）， and compare the vibration reduction effect with the vibration reduction controller designed by proportional integral derivative（PID）. Finally， the simulation model is built and verified by Matlab/Simulink. The results show that the geometric design method can intuitively obtain the existence， uniqueness and optimality of the optimal controller in the limited frequency domain， and the optimal vibration reduction control for the main control object can be as high as 25 dB. Compared with traditional control methods， the geometric design method has obvious advantages.