Seismic interpretation, field investigations and magnetic fabrics study reveal a week Cenozoic tectonic compressive deformation occurred in the northern Longmenshan front belt, which changed the older structures formed during the Late Triassic. So the front belt of the Northern Longmenshan exhibits a double-layer structural style characterized by shallow thrust structures of early deformation and deep blind ones of Cenozoic. The Kuangshanliang and Tianjingshan present a duplex which comprises of a shallow fault-bend fold of late Triassic and a deep blind stacking anticline imbricated by several thrust sheets of Cenozoic. And Qinglinkou and Zhongba shows a shallow imbricate structure of late Triassic and a blind fault-bend fold or fault-propagation fold which may be created or altered in the Cenozoic. The Cenozoic deformation intensity becomes much weaker from the north to south and results in the smaller displacement and structural uplift of the thrust folds. Magnetic fabrics study in the Jurassic and Cretaceous also illustrate the degressive distribution of the week Cenozoic deformation of the Northern Longmenshan front belt from the north to south, where the sedimentary magnetic fabric changes to initial deformation magnetic fabric and finally to pencil-shaped magnetic fabric from the Sichuan basin to thrust belt and initial deformation magnetic fabrics to pencil-shaped magnetic fabrics from the south to north along the northern frontier Longmenshan belt.