Development of Triassic lithofacies and palaeogeography can be divided into 5 stages in Qamdo area. There were not only inheritances but also differentiations in palaeotectonic and palaeogeographic frameworks of different stages. Palaeogeography of the Early Triassic inherited that of the end of the Late Permian, palaeocontinental area enlarged, and marine sediments only occupied narrow area; and from then, embryonic grillwork of islandsea displayed in arcbasin systems. In the Middle Triassic, arcbasin systems of Early Triassic were inherited, and intraarc basin largely depressed and accumulated thick multisource turbidity rocks and episodic arc volcanic rocks. In Early Carnian of the Late Triassic, molasse sediments developed, and shelf, slope and basin deposits only occurred in local areas. In Early Norian of the Late Triassic, the largest scale transgression had taken place the  whole area, carbonate sediments onlapped on palaeocontinent eastwards and westwards, and framework of islandsea from arcbasin systems was extinct from then. After Late Norian of the Late Triassic, water retreated from north and west, and seacontinental transitional and littoral terrigenous deposits covered the whole area. It turns out that there was an islandsea framework in the Triassic in Qamdo area similar to that in Indonesia and Haiti today.