Abstract: There are lots of Permian large-superlarge coal mines in South Gobi province of Mongolia along the border area between China and Mongolia, and the strata are composed of coarse clastic rocks dominated by conglomerate and coal-bearing beds intercalated with volcanic rocks. Besides, Permian strata around Yingen-Ejin Banner basin comprise a suite of littoral facies deposits, which are mainly clastic rocks, carbonate rocks and volcanic rocks. Drilling data obtained from Xirehada-Saihantaolai area in Yingen-Ejin Banner basin revealed that there is a set of coarse clastic rock and coal-bearing beds intercalated with volcanic rocks, which are remarkably different from lithic associations of each era in the periphery of Yingen-Ejin Banner basin but are consistent with the characteristics of Permian lithic associations in South Gobi province, Mongolia. Based on the comparisons of characteristics of Permian stratigraphic sequences and lithic associations along the border area between China and Mongolia and the study of stratigraphic ages of coal-bearing strata discovered by drilling in Xirehada-Saihantaolai area, the authors assign the Yingen-Ejin Banner basin to Permian. Combined with the characteristics of sedimentary sequences, the authors have gained a better understanding of the Permian sedimentary evolution and the planar distribution features of sedimentary facies, which provides some new evidence for the research on Carboniferous-Permian structural evolution in Yingen-Ejin Banner basin and its vicinities.