Abstract: Combined with the acquisition data from experiments of stealthy device in air duct and some turbofan engine,the paper studies the methods and steps of processing and analyzing dynamic pressure signals based on the wavelet theory.The results show that the power spectrum magnitude of signals is mainly fastened within 100 Hz,both range and turbulence of signals are augmented while rotating speed of engine is raised.The lower is the rotating speed,the more intensive are the vortices.It is confirmed that there is a strange attractor in turbulent fluctuation pressure system of flow field,and the correlation dimension D tends from 5 to 6.