Abstract: By using the seismic, well logging and drilling information, the Donghe sandstone unconformity complex in Tazhong?40 oilfield of Tarim basin is divided into homogeneous section, upper cross?bedding section and conglomeratic sandstone section, identifying the bottom unconformity of the conglomeratic sandstone section, establishing the unconformity complex sequence and lithologic structure classification, by which the porosity, permeability and oil saturation of strata with different sequential structures in the complex are quantitatively analyzed. The results show that the structures of the sequence stratigraphy of Donghe sandstone unconformity complex include Type?I1 and I2 with local Type?I4, the lithological structure belongs to Sub?Type?I2 and II2. The underlying transgressive systems tract (TST) of the unconformity complex is dominated by sand sediment, with high porosity and permeability as well as relatively poor oil saturation; the highstand systems tract (HST) is dominated by sandstone sediment, with relatively high porosity, permeability and oil saturation, developing a set of mudstone and siltstone barrier on the top of it, and fault?unconformity sheltered and fault?anticline reservoirs. The overlying lowstand systems tract (LST) of the unconformity complex is characterized by sand?mud interbedded sediments, with relatively high porosity, permeability and oil saturation, mainly developing fault?lithologic reservoir. Its TST is characterized by arenaceous mudstone, poor porosity and permeability, and medium oil saturation, mainly developing fault?lithologic reservoir