Abstract: The instantaneous parameters of seismic wave, suchas instantaneous amplitude, instantaneous frequency, and instantaneous phase, are of very important role in studying prop-erties of the earth. Basedon thedefinition of wavelet, the authors revised the Morlet wavelet and discussed the characteristics of revised wavelet indetailed. Theoretically analysis shows that the effect of wavelet transforms is restricted by the parameters suchas shape, leng th of wavelet, central frequency, b and width, as well as the number of wavelets,especially the rela-tionship among shape, central frequency, and b and width play a key role in wavelet transform. In the actual treatment of seismicrecords, we can choose proper parameter of shape. At mean time, we need give correct central frequency of wavelet to avoid omitting and redundancy of o-riginal message during wavelet transform. At the end of the artic le, the field record isdemon-strated as result of wavelet transform according to the concept of instantaneous amplitude and instantaneous phase.

Key words: Wavelet transform, Parameter of shape, Central frequency, Instantaneous am-plitude, Instantaneous phase