Abstract: The unconformity is an incoordinate connection kept in strata as a result of the depositional break.The vertical structures of unconformity can be divided into 3 layers: rocks above the unconformity interface,weathering clay and paleokarst zone.they not only are the pathways for oil and gas migration,but also provide accommodation for oil and gas accumulation.Simulation experiments show that the hydrocarbon migration along the vertical structures of unconformity is not only controlled by petrophysics and slope gradient,but also can breakthrough the weathering clay in the weak links to flow with communication between zones;Stratigraphic overlap hydrocarbon reservoirs on the surface of unconformity are more easily to form than stratigraphic screened hydrocarbon reservoirs under the surface of unconformity.