Coulomb’s law of failure or related Anderson’s theory of faulting, which were deduced from rock mechanics experiments under small strain, can not always reasonably explain formation mechanisms of fault systems, because a majority of fault systems are related to the deformation processes of large strain. Physical modeling, a very useful method for structural deformation study, can shed new light on the formation mechanisms of fault system: many fault systems which were originally considered of complicated genesis, may actually be the results of simple deformation processes and need no complicated dynamical interpretations. In this paper, some typical study cases, concerning extension, compression and inversion tectonics, are shown to illustrate that physical modeling can give some new insights for the formation mechanisms of fault systems.