In order to improve Empirical Mode Decomposition (EMD) quality and decrease mode mixing and reflect the device vibration mode by the resulted intrinsic mode function (IMF) series gained through decomposition, synthesized filter design is introduced. With regard to the EMD deficiencies in terms of signal processing, the synthesized filter above, which makes full use of the wavelet d-enoising ability and median filter restraints on pulse disturbance, is used to preprocess the data that is to be decomposed. With the method being applied to aero-engine vibration signal processing, each IMF filtration times and EMD decomposition levels can be effectively reduced, the cumulative function of end effect in the decomposition process can be weakened, and then the mode mixing phenomena will be restrained. The decomposition results show that decomposition with the synthe sized filter can better reflect engine vibration mode and operating condition and can obtain the data components that can represent high-pressure rotor and low-pressure rotor vibration characteristics. Therefore, it has laid a foundation for later characteristic sampling and fault diagnosis.