The sedimentary rocks of the Lower Carboniferous Nanmingshui Group in the northeast margin of the Junggar Basin are depositional process response to the oceanic crust subduction in the Late Paleozoic, north Xinjiang area. Abundant ichnology fossils were found in the Nanmingshui Group. The characteristic of lithology, sequence evolution and geochemistry values of sandstone and mudstone indicate that the Nanmingshui Group deposited in a back arc basin. The Early Carboniferous oceanic crust subduction in the east Junggar Basin was the dynamic mechanism for the back arc basin formation in the margin of northeast Junggar Basin.