Abstract: In the book Haiyuan Active Faulting Zone,a 12 14.5 km maximum horizontal displacement was proposed for the north flank fault of the Nanhuashan Xihuashan Mountain.Recent research suggests,on the basis of geological mapping and re subdivision of the stratigraphic sequence,that the evidence for the above mentioned displacement is insufficient.Details of such questioning are given in terms of stratigraphy,petrology and fracturing mechanism.