Adapting the self-adaption time-frequency analysis method, through the theoretical analysis and digital simulation the study of relative numeral and applied characteristics has been done in this paper. According to the principle of the flutter test and the characteristics of the signal, the two time-frequancy field filtering algorithms are led to research on the flutter boundary prediction of the subcritical response of the aeroplane structure. Through the joint time-frequency analysis (JTFA) and the time-frequency field filtering, the effective signal and the model parameter are picked up and the flutter boundary is predicted. The desired result is achieved.