Abstract: Spectral imaging technology, which mainly follows the tuning principle in thin layer, can characterize the non-continuity of geological reflecting layer in thickness and non-isotropy of lithology.The algorithm used in the past was usually based on Fourier transform, but there are clearly limitations in the method, because the seismic amplitude spectrum that it evaluated is the function of time windows.If the time window is too short, the amplitude spectrum will be in convolution with transform window function and lose local characteristic of frequency.It can improve the resolution of frequency to increase the length of time window, but if the time window is too long, it is hard to distinguish the characteristics of amplitude spectrum in single reflection, because many reflections in the time window will make the amplitude spectrum using flute marks as its characteristics.Since it is hard to choose time window in practice and analyze the error quantitatively, there are usually deviations in the evaluation of amplitude spectrum.The time and spectrum analysis technology that based on wavelet transform becomes a important tool in the analysis of non-stationary signal, and replaces Fourier transform in practice.The instant spectrum analysis technology of this kind can get precise results of time and frequency analysis, and avoid the problem of time window.It can indicate the vertical variation of the reservoir layer in time and thickness and the horizontal non-continuity, and let the researcher describe the characteristics of reservoir layer and spatial variation quickly and effectively.