The Late Triassic Northern Qiangtang Foreland Basin is a peripheral one situated to the south of the Jinshajiang suture zone, to the south of the basin is a forebulge(center uplift). The basin was filled with Late Triassic Xiaochaka group, in thickness more than 2 500 m, which could be divided into two tectonic sequences bounded by unconformities. In a transverse section there is a wedge-shaped sedimentary body with thicker in the north and thinner in the south with double paleocurrents and double provenances: the Hoh Xil thrust belt in the north and the forebulge in the south. The depocenter was located in north part of the basin. The sedimentary and tectonic evolution of the basin can be divided into two phases by stratigraphic signatures. The early one was flysch phase, characterized with the carbonate ramp developing along the north slope of the forebulge and the turbidite occurring along the south margin of the Hoh Xil thrust belt respectively. This phase should be coincident with subduction of the Jinshajiang Ocean and initial collision. The second one was molasse phase, during which the delta system developed along the north slope of the forebulge and the molasse deposits(alluvial apron as well as delta system)developed along the south margin of the Hoh Xil thrust belt respectively. This phase should be coincident with the collision followed the Jinshajiang ocean’s closure.