Abstract：In order to improve the mapping precision for low-amplitude structural zone and complex mountainous area in Junggar basin, we used multi-velocity study method to carry out study on velocity distribution rule in Junggar basin and achieved primary results. The paper analyzed the key factors affecting the velocity precision, considered that acquisition parameters in the field, static correction method and values, processing factors, surface conditions and seismic and geologic data determined the velocity precision and presented idea, method and flow studying velocity in complex structural area, which adopted multiple key techniques in first time, developed fine velocity study of 3D model in desert area of basin hinterland and in complex structural area of south margin, implementing the velocity-variant mapping, which provided the foundation for identifying low-amplitude traps and traps in complex mountainous area.
