Abstract: The Lower-Middle Devonian Kulumudi Formation of the Barluk Mountain area in west Junggar of Xinjiang has been widely considered to be product of the coastal neritic deposition environment. Through mapping Ⅰ, Ⅱ lithofacies section of Kulumudi Formation, and in combination with lithology, sedimentary structure, thickness, fossils and other characteristics of Kulumudi Foramtion in the study area, the authors studied characteristics of sedimentary rock and facies as well as sedimentary sequence, and detected through analysis that Kulumudi Formation is composed of alluvial fan, fan delta and coastal-shallow sea facies. On such a basis, the authors put forward a sedimentary model of the Early-Middle Devonian period, which can provide certain basic geological data for the late stage regional geological survey work.