Abstract: The Frame-synchronized wavelet packet transform algorithms are introduced in the paper. The algorithms not only have the advantages of the variable time-frequency windows of waelet packet, but also can analyse signals in a STFT-like frame-by-frame way. So they not only can reduce the analysis time-window length to fit the requirement of real-time speech analysis, but also can perform the best analysis in frequency domain, and meanwhile they are the fast algorithms as well as the FFT algorithm. We have simulated auditory model by using the algorithms and applied them to speech enhancement. That the better result has been obtained at SNR= -5 dB has been shown in the experiments. The algorithms also can be used for speech coding, synthesis and recognition.