In order to systematically characterize the distribution characteristics of fault-sandstone composite transport system and accurately describe its dominate migration pathways，Shale Gouge Ratio method（SGR）is used to quantitatively characterize the transport capacity of faults and determine the transport faults and lateral transport positions during the hydrocarbon accumulation. Connectivity probability method is used to quantitatively characterize the conductivity of sandstone transport layer and determine the dominant migration pathways of sandstone transport layer. Three-dimensional seismic data is used to depict the spatial distribution of fault planes，and it is used to determine the convex ridge of oil source fault by combining the buried depth of fault plane. Based on the results of paleogeomorphology restoration，the distribution of tectonic ridges is determined. By coupling the transport faults，sandstone transport layers，cross-section ridges of oil source faults and structural ridges，the characterization of dominant migration pathways in the fault-sandstone composite transport system is realized. The results show that there are mainly two types of composite transport system in the Es1 Member in Qinan Slope of Qikou Sag. One is the ridge of Nandagang Fault（oil source fault）-sandstone transport layer-transport fault-tectonic ridge. The other is sandstone transport layer-tectonic ridge-fault. The location of reservoir and hydrocarbon show of wells in different periods are in good agreement with the characterization results，which indicates that this method is effective for fine characterization of fault-sandstone composite transport system.