Abstract: The eastern foot of Helan Mts, locating at the juncture between the fault block of Erdousi and Alashan, is a famous active fracture zone and also the northern end of the earthquake belt which strethes from south to north in China. The fracture zone, which has 120 km long, 10-15 km wide, running 38° NE, consisted of a series of normal fault. It controled the evolution of the Quaternary environment in the eastern and western of the mountains. The west is the fault block of Helan Mts whose highest peak is 3556 m , and has been raised since late Mesozoic era and dissected intensily, developed diluvial fan. The east is the depressed graben of Yinchuan plain which altitude is 1100-1300 m, and showed a landform of block Mts and depressing basin which are controlod by Huanghe fracture of the eastern of Yinchuan graben.
The study indicated that about 4 times tectonic movement have occured in the fracture zone and relative stable period is decreasing. The zone formed step-shape toward the centre of basin because of the plate movement of Indian and Pacific and also extruded by Qing-Zang plateau rising. Three Sections of geomorphologic land stape in eastern Helan Mts not only are controled by the fault zone, but also related to ancient earthquake action in both pinlou and Yinchuan areas.