Abstract: In the complex structure area，especially the high steep structural region where the thrust belt is well developed，the structural map which is based on the conventional velocity analyzing and conventional mapping is not so precious and can′t meet the production requirements.The paper has made an intensive study on building velocity-field model in the submountain high steep structural region and structure mapping.Based on the former sucessful experience，it builds velocity fields in upper wall and foot wall respectively and restricts the internal velocity with the changeing law of drilling velocity.A velocity-field model building and mapping method for the complex structure areas is summed up.The practical applications in south margin of Junggar Basin show that this method can improve the precision of building velocity field and structure mapping in compex structure areas，and has a good application prospect.

Key words: stacking velocity, velocity field building, variable-velocity structure mapping, thrust fault