Abstract: The paper proposed a new concept of fault-plane structural system,taking Wangjiagang oilfield for an example.Based on a detailed description of the characteristics of fault-plane structural systems,their shielding capability for oil and gas is studied,and then the sealing properties on different parts of different fault planes are appreciated.The paper also approached to the role of a fault-plane structural system on oil and gas enrichment,and suggested that "planar anticline" and "planar nose" fault-plane traps are new areas of oil/gas exploration.