Abstract The measured signals from the casing of an aero-engine are the mixture of the vibration caused by the low pressure rotor, the high pressure rotor and the other rotating parts. In order to separate the vibration reduced by every different vibration source, this paper investigated aero-engine vibration signal blind source separation method based on the independent component analysis. Firstly, a blind source separation algorithm based on maximum signal to noise ratio was expounded in this paper, the algorithm was adopted to separate initial signals and the output was consistent well with the source signal. It was validated that the algorithm was of correctness and feasibility. Secondly, combination of the above algorithm with FFT separation method was used in the blind source separation of measured vibration signals. It was proved that the method was effective to separate the high-pressure rotor vibration and the low-pressure rotor vibration of a twin-spool aero-engine. It has some advantages, such as less iteration times, simple calculation process and a high stability. This paper presents a feasible and effective signal processing method of fault diagnosis and vibration monitoring for twin-spool aero-engines.