Miaopo,Baota,Linxiang(Jiancaogou),Wufeng and Guanyinqiao Formations were formed during the Late Ordovician in the Middle-Upper Yangtze Region. Based on outcrops and cores observations,combining with the previous research,the lithology,palaeontology,ecology and laboratory analysis were used to divide the facies into tidal flat,shallow marine shelf,and deep water basin facies in study area.Among them,tidal flat facies was characterized by the deposits of limestones,dolomites,calcareous siltstones and siltstones. Shallow marine shelf facies was mainly composed of “chapping grain”limestones,nodular limestones,shales and silty shales. While black carbonaceous shales,silty shales,and siliceous shales were deposited in the deep water basin,which predominantly produced graptolite assemblages living by floating camp. The lithofacies palaeogeographic analysis shows that there was a strong inter-plate collision and extrusion in the South China Plate,which was influenced by the Caledonian Tectonic Movement in the Late Sandbian-Early Katian Age of the Late Ordovician. During that period,the Central Sichuan and Western Sichuan-Central Yunnan-Central Guizhou-Xuefeng Uplifts gradually swelled up and expanded,meanwhile the relative sea level rose and the rimmed carbonate platform was submerged and deposited a wide range of shallow marine shelf facies “chapping grain”and nodular limestones.In the late Katian and Hirnantian Age of the Late Ordovician,those uplifts continued to expand,and the Middle-Upper Yangtze region mostly began to deposit black carbonaceous shales,silty shales and siliceous shales in the limits of uplifts movements.Especially for the Yibin-Luzhou area in southeastern Sichuan,Wangcang-Nanjiang area in northern Sichuan and the Wulong-Daozhen area in eastern Chongqing and northern Guizhou,the black siliceous and carbonaceous shales show good hydrocarbon potential,and could be the key study areas for the further exploration and development for source rocks and shale gas.