Based on plane wave decomposition, We propose a wave-equation depth migration method for prestack seismic data. Through the decompositions to common-shot gathers and common-offset gathers, one can obtain common p, plane wave gathers and common p(h) plane wave gathers which are suitable to the single square root extrapolation equation and the double square root extrapolation equation, respectively. During the decompositions to common-shot gathers and common-offset gathers, one doesn't need the calculation of tau-p transformation in common sense. By the comparison of the migration results from the common p. plane wave gathers and common p(h) plane wave gathers, we think that, for the media with weak variation of velocity in lateral direction, the migration results are the same. However, for the media with strong variation of velocity in lateral direction, the migration result from the migration method for the common p, plane wave gathers is superior to that from the migration method for the common p(h) plane wave gathers. As for calculation efficiency, the migration method of common p. plane wave gathers is basically the same as that of common p(h) plane wave gathers.
