The geometric and kinematics characteristics,activity segmentation and seismic risk of northern piedmont fault of Changling mountain in Gulang county,Gansu province are studied through the field investigation,trench excavation and b-value calculation.The results show that the northern piedmont fault of Changlin mountain can be divided into four secondary faults,distributes as an inverse ＂S＂ style in whole,and was active in early and middle stage of Holocene.For the latest motions,f1 at west acted as normal fault with left-lateral moving inclined to south,section f2 at west and section f3 at middle segment acted as normal fault with left-lateral moving inclined to north,while east segment f4 acted as normal fault inclined to south again.The west end of the fault is partitioned with Gulang fault by Qinjiadashan mountain and Tertiary fold system,and the east end of the fault is partitioned with Guanguanling fault by Baidunzi left-lateral pull-apart basin with step distance of 3.5 km.Due to the elapsed time of the last seismic action being very long and the modern stress quick accumulation,the fault area has high seismic risk in future time.