Although most researchers both in China and abroad have agreed that the Tibetan plateau is the largest highland induced by the India-Asia collision over the past 60~50 Ma, its formation mechanism has long been a problem of controversy. Deep seismic reflection profiling is an effective technique for revealing the fine structure of the lithosphere and detecting the deformation style of the crust. The reprocessing of the deep seismic reflection profile across Songpan block-West Qinling orogenic belt has revealed the details of lithosphere deformation. The superimposition of the thrust duplex structure in the upper crust and a sub-horizontal detachment in the middle crust and the vertical stacking of Moho at the bottom of the crust show that the lithospheric shortening deformation on the northeastern margin of the Tibetan Plateau was the main formation mechanism. The Kunlun fault 1000 km in length, one of the largest continental-scale strike-slip faults in Tibet, terminates at a sub-horizontal decollement with the depth of 35 km in the lowermost crust of Tibet. The study establishing the vertical structure of the lithosphere shows tectonic relationship between the western Qinling orogenic belt and the Zoige basin on the lithosphere scale.