| Songpan-aba area is situated in the center of China's continental tectonics. It is in the conjunction of the North China plate, Yangtze plate and Qiangtang block, and composes the eastern margin of Tibetan plateau. It is also the important tectonic unit where china's main blocks and orogens converge and superimpose. Permian and Triassic is not only the main period of Songpan-aba sedimentary basin's evolution, but also the important time which various deformations and tectonic movements emerge. So the researches are done which include stratigraphic classification and correlation, identifying and analysing important unconformities and their corresponding tectonic events and judging the property of sedimentary basin. What's more, at the base of upper researches, the basin's filling process and tectonic evolution history are restored. All these researches will be great meanings towards exploratory development of sedimentary mineral products and helpful to the science discuss of geologic problems in this area.At the basis of field exploration, and combining others'research fruits, formation researches of Permian and Triassic are held at the eastern margin of songpan-aba area. The job includes two aspects. One is multiple stratigraphic classification and correlation which contains lithostratigraphy, biostratum, chronostratigraphy. The other is to identify and analyse important unconformities and their corresponding tectonic events. According to the stratigraphic correlation, such opinions are implied that different blocks of the eastern margin of Songpan-aba area lie in the same tectonic settings, have the same sea level rising-falling cycle and similar paleontological characteristics. The only difference is that different parts have different sedimentary facies. The Songpan-aba area of this period have four important unconformities, which happen respectively in Early Permain, the junction of Middle and Late Permian, the meeting of Permian and Triassic, and between the Anisian and Ladinian. These four unconformities correspond respectively four tectonic events which are the west part of tethys Ocean closure event, Dongwu movement, global sea level change event between Permian and Triassic, and the transformation of tectonic settings event.By geochemical analysis of Permian volcanic rocks, we conclude that the Late Permian basalt mainly belongs to continental rift basalts, and resulted from the Emeishan mantle plume. The eruption of basalt results in the emergence of Garze-litang rift and Longmenshan rift at Late Permian. The geochemical characteristics of flysch sandstone and mudstone which depositted after Ladinian suggest that the sediment provenance have the property of continental island arc. Combining the discusses of flysch prototype basin which is called Baryan Har basin, we know that the Baryan Har basin is a large-scale back-arc basin resulted from intensively depression of back-arc area. It formed after tectonic setting transforms to pressure from extension and is at the same time as development of Yidun island arc.At the base of upper chapters'researches, the evolution history of Permian and Triassic sedimentary basin at eastern margin of Songpan-aba area can be divided into four phases: First is passive continental margin basin phase during Early and Middle Permian; Second is continental cracking and rift forming phase at the time of Late Permian; Third is rift extension and faulted depression phase during Early Triassic and early period of Middle Triassic; Fourth is basin depression and compensated filling phase from later period of Middle Triassic to early period of Latter Triassic, Fifth is basin suppression and closure phase from late period of Late Triassic to Jurassic period. The basin's continental tectonic settings and its evolution of each phase is also discussed, and the lithofacies palaeogeographies of each phase are analyzed elementarily. At the same time, the tectonic palaeogeography and sedimentary basin evolution model diagrams are drawn.
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