Differential thrust system formed in late period of tectonic activity in western Taibei Sag has a close relationship with structural framework, hydrocarbon migration and accumulation in this area. Near east -west direction thrust fault system and north- south direction strike- slip fault system divide the western area into several chess-board structural blocks. East -west direction thrust fault system obstructs oil/gas and controls hydrocarbon distribution, while north- south direction strike- slip fault system plays a role in communicating deep oil/gas, which makes the vertical migration and seals oil/gas to form reservoir block. The depositional thickness of the main hydrocarbon bearing sands varies greatly, which makes the joint of the sand and mud possible. Both the strikeslip fault and lithologies are responsible for the forming of structural- lithologic reservoirs in western Taibei, with the influence of lateral lithological pinchout or disconnected sand body. According to differential thrust system and hydrocarbon distribution rules, a great exploration potential is predicted in faulted fold zone in the middle sag and thrust anticline and fault bench in piedmont of northern sag.