Abstract: Data collected by sub-bottom profiler and single seismic is always recorded in SEGY data files of binary coding, with position information saved in data head. Usually, the position in the head is not the real position of sources, but the coordinates of the GPS antenna or navigation reference point. There is a fixed offset between the two. We often process these data using such seismic processing systems as OMEGA, SU and RadExpro, and never consider the offset of positioning data. This will certainly affect the precision of the geological interpretation in subsequent processing. In this research, we recommend matching the headings from the navigation data and the coordination from SEGY files, re-computing the coordination of the source on the basis of relative position between the source and the position recorded in a SEGY file, and re-writing the SEGY data files. The method can provide correct geographic position for comprehensive data interpretation.