Fault facies are the natural extension of the facies concept into the realm of faulted rock bodies. This approach is succeeded in describing the architecture and petrophysical properties of fault and fault structural elements accurately. Faults exhibit an obviously fault  parallel zonation which mainly includes damage zones and induced fracture zones in space. Structural elements are the basic units which constitute the fault volumetric architecture and are the fundamental objects of fault facies study. Through depicting the deformation characteristics of typical fault envelope precisely using the fault analysis approach,  how the analysis methods of fault facies to be used actually is introduced and the facies model of extensional fault in siliciclastic rocks is also founded finally. It is shown that the analysis approach of fault facies has great significance in the study  of the closure property and the stability of fault facies. In addition, this approach has a broad application to the accumulation, exploration and development of oil and gas fields as well as engineering constructions.