Abstract: Taking 2D homogeneous medium velocity model as example,by using the first-order and second-order wave equation with input wavelet of different phase Ricker wavelet,we carried out numerical simulation.The computation results show that there is a large difference between the wave field response of the first-order wave equation and the input wavelet waveform,as well as the phase shift.Meanwhile,the ratio amplitude spectrum has linear proportional relationship with frequency.However,the wave field response characteristics of the second-order wave equation and the input wavelet waveform are almost the same with small phase shift,and the ratio amplitude spectrum is almost not changed with the frequency.Therefore,the second-order wave equation has the property of shape preservation,and can achieve forward modeling with expected wavelet form.Based on the above analysis,the response characteristic of inverse time wavefield was discussed,then,the correlation type and reflectivity type reverse-time migration on the 1D layered model was carried out.The results show that if the wavelet waveform of the source wave field and receive wave field are consistent,the image results are the best with lowest low frequency reverse-time noise;otherwise,there is a time shift between the reflection interface on the imaging section and actual formation interface,and the energy of the low frequency reverse-time noise is stronger.Therefore,maintaining the consistence of wavelet waveform is the prerequisite of the high-precision correlation and reflectivity reverse-time migration.