Abstract: In this paper, many factors about fault gouge resulting in the uncertainty of fault gouge dating result are regarded, the possible results of the uncertainty caused by these factors are analyzed, and the geochronological significance of fault gouge dating and its application in research on active faults are discussed. The results of fault gouge dating may be regarded as the maximum limit of the latest active age of fault, and the latest age of fault active should be younger than the dating results. The dating results of fault gouge may be used to determine that a fault is active, but it could not be used to determine that a fault is inactive, and extraordinarily could not be used to determine that a creep fault or segment is inactive. The difference of fault gouge dating results in many faults or segments would reflect the difference of their active intensity rather than that of their active age.