The analysis of systematic statistics of Ordovician fault characteristics in Tahe in this paper shows that the large karst caves most probably distributed in the caves which are below the boundary of T74 and mostly controlled by mid-large faults.According to the relationship between faults and the development of karst caves,the concepts of “fault which could control karst caves” and “fault which controlled by karst caves” have been proposed,and it is believed in this paper that middle-large faults in Tahe are mainly “fault which could control karst caves”,but the small fractures in this area are mostly “fault which controlled by karst caves”.On the basis of the theory of “fault which could control karst caves”,the mode of “fault-paleokarst” in Ordovician of Tahe area has been established.