The eastern section of the North Qilian fault zone lies on the northeastern edge of the Qinghai—Tibet Plateau uplift zone,which consists of the Jinqianghe fault,Laohushan fault,and Maomaoshan fault.The Haiyuan fault,located in the west of the Ordos Block,is a NW trending,large strike-slip fault.It has good continuity with the eastern segment of the North Qilian Mountain fault,and both exhibit left-type dislocation.Therefore,the eastern segment of the North Qilian Mountain fault and the narrow Haiyuan fault are collectively referred to as the generalized Haiyuan fault zone.Seismic activity is very strong in this area,where many M_S≥7.0 earthquakes have occurred over time,such as the famous 1920 Haiyuan M_S8.5 earthquake and the 1927 Gulang M_S8.0 earthquake.Therefore,the region's seismic hazards should be carefully investigated.Based on the measurement results of the mercury and radon concentrations of 10 fault-gas profiles in the generalized Haiyuan fault zone,in this paper,we describe our detailed analysis of the spatial distribution characteristics of the mercury and radon concentrations in different segments and their overall distribution trend along the fault zone.Combined with the seismotectonic background and spatio-temporal evolution characteristics of large earthquakes,as well as the spatial distribution characteristics of the b-value,we studied the relationship between the spatial distribution characteristics of fault gas and the seismic risk of different segments in the generalized Haiyuan fault zone.The results show that the intensity of the fault-gas concentration in the fault zone exhibits obvious segmentation,and is also correlated to some degree with the seismic activity.Based on the above research,we made a pre-judgment of the potential seismic risk in different segments of the generalized Haiyuan fault zone from the geochemistry perspective.This research can provide vital background information for earthquake prediction in the study area.