The rotating blade is a key wearing part of aero-engine

so it is necessary to monitor its condition. Blade tip timing (BTT) is an effective non-contact monitoring method for rotating blades. However

the traditional BTT relies heavily on the once-per-revolution signal

and the BTT signal has serious under-sampling problem. In this paper

Orthogonal matching pursuit (OMP) method based on blade vibration difference is proposed to extract blade natural frequency. Firstly

a BTT sensor is used to calculate the blade vibration difference. Then

the sparse model of blade vibration difference is constructed

and the blade vibration difference signal is decomposed by OMP method under the condition of varying speed

and the vibration amplitude and natural frequency of the blades are extracted. The effectiveness and robustness of the proposed method are verified by numerical simulation

and experiments are carried out on the blade tip timing test bench. The results show that this method can accurately identify the amplitude and natural frequency of blade asynchronous vibration.