Abstract: The wavelet transform is the most recently technique for processing signals with time-varying spectra.A wavelet transform signal processor based on continuous wavelet transform has been proposed by several authors for processing ultrasonic signals.In this paper,wavelet transform signal processor parameter optimizing in ultrasonic flaw detection is studied as viewed from time-frequency localization.Additionally,the determinate methods of the parameters,such as the mother wavelet,the frequency-to-bandwidth ratio of the mother wavelet,the number of filters and etc.,are also given.Finally,the experiment verification is performed.