Abstract: Acording to microscopic analysis of the data on the grain size and clay mineral compositions, as well as the surface textures of quartz grains in the fault gouges, we estimate the Subao fault was activated during the Pliocene to the Early Pleistocene, and was activated again in the Middle Pleistocene, the Chiyu fault was formed by the separate faulting of the different occurrence fault during the late Middle Pleistocene to early Late Pleistocene, They have not had any activity since the Holecene. The results of the microscopic analysis coincide with the geological information observed from the field.