Abstract: In order to improve the velocity analysis precision of the low SNR seismic data and to get reliably velocity information, on the basis of 2D seismic prospecting, the technical process of "preferred gathers velocity analysis, NMO correction, F-K filtering, InvNMO correction, high density fine velocity analysis" was used to investigate the geological targets of deep concealed faulted structures in Guanzhong area for seismic data with low signal-to-noise ratio, which makes the velocity spectrum energy group gathered. It can not only effectively improve the precision of velocity analysis of seismic data with low signal-to-noise ratio, but also suppress the noise. And then the medium and deep velocity field information with high quality and imaging profile data were got.