The sensitivity of fault diagnosis of aero-engine rolling bearing based on the vibration signal measured on the casing was studied. Firstly

the impulse response test was performed by two aero-engine rotor test rigs with casing. The response from both bearing housing and casing

which was caused by the impulse excitation from the location of rolling bearing

was measured and their differences were compared further. Secondly

the fault simulation test of rolling bearing was performed by these two aero-engine rotor test rigs. The time domain waveform

frequency spectrum and wavelet envelope spectrum of the signal measured on the casing were compared in detail with those of the signal measured on the bearing housing. The results show that when the coupling stiffness between rolling bearing and casing is small

there is a large attenuation of the vibration signal of faulty rolling bearing transmitted to the casing. However

by means of traditional envelope demodulation method based on wavelet transformation

the faults of outer and inner races still can be diagnosed well

but the diagnosis effect for rolling element is not as good as that for outer and inner races. The research results provide a test basis for actual fault diagnosis of aero-engine rolling bearing based on the vibration signal measured on the casing.