Abstract: The huge-thick loess area in Erdos basin has complex surface conditions and the thickness of low velocity zone is various. The quality of straight-line survey is relatively bad, with terrible signal-to-noise ratio and resolution, and the survey grid of crooked-lines along ravines is sparse, thus the utility of seismic data is too limited to satisfy current lithology exploration. The off-line seismic exploration technique developed in loess plateau area by theory and test absorbed advantages from crooked line and multi-line exploration techniques in loess plateau area, as well as the 3D seismic exploration technique, not only avoiding the near offset strong noise, but also expanding the azimuth for the stacking trace gathers. According to the characteristics of off-line seismic data and under the guidance of relative amplitude preserved processing idea, through technical research of off-line seismic data processing, a 3D static correction technique for off-line seismic data was proposed, 3D noise suppression module was applied innovatively to suppress the coherent noise of off-line seismic data, the concept of well-controlled based on VSP synthetic record was improved and formed the off-line seismic data processing technology in huge-thick loess plateau area with low SNR.