Abstract: Based on the structural styles classification of J.D. Lowell, detailed classification and study of structural styles in the studiedarea are made, and possible natural gas traps in these structural styles are investigated. Considering whether the basement being involvedor not, the structural styles could be divided into two major types like basement involvement and caprock detachment. According to thedifferent stress env ironments and the different structural assemblages, nine basic structural styles are identified. The study shows that de-velopment of the structural styles is primarily controlled by the compresso-shear stress field with near S-N orientation occurred in faultdepression stage, while the late compressive stress field with NW-SE orientation only has a minor controlling process. Each of structural .styles has its control to the gas accumulation in some degree. Among them, the anticline, anticline-faulted traps developed in assemblageof half graben-like and fault convex controlled by low angle boundary fault, syn-sedimentary compressive anticline, thrust-fold assemblage,fault-bended anticline and its overlaying syn-sedimentary anticline are in favour of natural gas accumulation in Xujiaweizi area of north-ern Songliao basin.

Key words: Keywords: Songliao basin;Xujiaweizi oil field, structure, natural gas;trap