Abstract: Development of faults and their internal structure changes exert great influence on oil-gas migration and accumulation in hydrocarbon-bearing basins. Based on previous studies and fault outcrop observations, the present study integrated the division of fault zones with the information on seismic, drilling, imaging logging, etc. to qualitatively classify internal structures of faults, calibrate conventional logging scales and sum up logging response characteristics. Quantitative analyses were carried out on internal structures by means of instruction curves and intersection mapping. The result revealed that fault zones were mainly composed of structural units with different deformation and properties in the central sliding breaking zones and the induced fracture zones on both the upper and lower plates, and there existed distinctly temporal and spatial differences in the internal structures of fault zones. Temporally, internal structures were different for the same fault but at different geological periods; spatially, fault zones had horizontal asymmetry, vertical stratification and segmentation along fault strike. These differences are just what that caused the heterogeneity of physical properties of different structural units within fault zones, which then makes temporal and spatial differences in abilities of hydrocarbon transporting and sealing by faults.