Detailed studies of petrology, palaeocurrent direction, paiaeogeomorphology and palaeohydrody-namics have been conducted for the Permian-Triassic Cangfanggou Group in the foredeep of the Bogda Mountains in the southeastern Junggar Basin, Xinjiang. Sedimentary environments and fades of alluvial fans and pebbly braided rivers, sandy braided rivers, meandering rivers, low-sinuosity rivers, swamps and fresh-water lakes are recognized in the group. Climate and tectonics of source areas strongly controlled the evolution of the sedimentary environments and facies in the foredeep. The block faulting in the Bogda Mountains increased the ground slope, which led to a drastic increase in the grain size of the sediments. Humid climate, being beneficial to plant growth, would provide protection of channel banks and at the same time weaken chemical weathering in the source area, thus large amounts of clay materials are available for the formation of clay plugs. As a result, stable banks and meandering river belts are