Diapirs are important hydrocarbon- bearing structures in the Yinggehai basin. Previous studies, limited by seismic and drilling data, have led to unclear interpretations of their internal structure, formation processes, and genetic types, significantly hindering further hydrocarbon exploration in these structures. Analysis of the latest ocean bottom nodes seismic data in the DF1- 1 diapir zone shows that, contrary to the poorly imaged ‘fuzzy zones’ seen in conventional towline seismic data, the diapir exhibits clear layered structure. This layering shows good correlation with adjacent strata, and there is no obvious large- scale lithological separation. The interior of the diapir contains multi- stage, multi- directional faults, with vertically overlapping fault systems forming deep- to- shallow pressure relief channels. The planar distribution of diapirs in the Yinggehai basin reflects the characteristics of these multi- stage and multi- directional faults. The homogenization temperature of fluid inclusions, hydrothermal minerals, and natural gas isotope characteristics indicate active thermal fluid activity in the diapir zone. Therefore, the diapirs developed in the Yinggehai basin are not traditional mud (salt) diapirs or magmatic diapirs but rather originate from fault- controlled fluid activity. This new understanding has important guiding significance for deepening and expanding hydrocarbon exploration in the diapir zones of the Yinggehai basin.