Abstract: Dating of fault is one of the important contents of studying the fault activity. However,different dating results are usually given for the same fault in some engineering site areas,it leads to dispute and can't make correct assessment of the fault activity.After our studying the regional stability of several large-scale engineering projects in last years,we have got some knowledge of the problem of fault activity evaluation.This paper presents some advances in study on fault dating,with an emphasis on the example of fault activity studied in Jiudianxia dam area on Taohe River,Gansu province.The main procedure of the study just is the integration of the isotopic dating,field geological investigation,and hacrostructure analysis.The research results of the faults in this paper will be valuable for the fault activity assessment and the key points to the fault dating by the methods.