Abstract: Based on the seismic and core data, slices and geochemical analytic data, this paper analyzes the geological factors of lower Es₁ tight sandstone oil in Qibei Slope of Qikou depression and clarifies the exploration potential in this area. The study indicates that the stable and gentle structural background of lower Es₁ in Qibei slope, high-quality source rock in a large area, distribution of heterogenerous tight sandstone reservoir in a large area, co-existence of source and reservoir and near-distance migration and accumulations are favorable for formation of tight oil on a large scale. Lower Es₁ of Qibei slop developed muti-times offshore subaqueous fan, the middle fan subfacies and the physical properties of reservoirs in the fault development zone are relatively desirable, leading to development of conventional oil reservoirs. The outer fan subfacies with development of thin tight sandstone distributed with tight oil in a large area, shaping a series of oil reservoirs overlapped vertically and horizontally with conventional oil reservoirs and tight sandstone oil reservoirs in this area. Based on prediction of reservoir, tight oil is estimated to be distributed in a 163km². The sweet-spot zone of the turbidite sand sheet in the upper section of Ban2 thin layer is the fi rst choice for tight oil exploration.