Qiangtang Basin can be divided into Northern Qiangtang Depression，the Center Uplift and Southern Qiangtang Depression. During the Early and Middle Triassic, Qiangtang Basin has the same framework of lithofacies and palaeogeography. Affected by marine transgression of Kekexili-Bayankala ocean trough, the Northern Qiangtang Depression depositted epicontinental sea sediments. At the same time, Southern Qiangtang and the Center Uplift were being denuded. Till to the Late Trassic, except to the west part of the Center Uplift, Qiangtang Basin was covered with water owing to the spreading of Bangonghu—Nujiang Ocean. Although the Northern Qiangtang Basin and Southern Qiangtang Basin were connected through Shuanghu strait, the origins of them were different, and their components of the tectonic and lithofacies were also different. The Southern Qiangtang Basin was an extensional marginal basin to the north of Bangonghu-Nujiang ocean, While the Northern Qiangtang Basin showed the character of foreland basins affected by Kekexili-Bayankala orogenic movement. The framework of lithofacies and palaeogeography had the feature of “Zonation along E-W,blocks in zones”, which was resulted from the regional tectonic evolution and basal faulting.