Based on the stages of tectonic activities and common characteristics of hydrocarbon reservoir forming, this study proposes a basic concept for fault-depression transformation system. Through detailed analyzing on the features of large-scale structure and stratigraphy, and reservoir types, it is believed that the "T" type transport system consisting of oil source fault and framework sands (unconformable surface) in the steep slope zone, multiple "T" type transport in the gentle slope zone, and "S" type paleogeomorohology are the key conditions to control the stratigraphic overlap pool formation.