The Zhuanglang river basin is situated in the eastern part of the Qilian Mountains. The principal geomorphic features of the river basin are as follows: 1. The current direction ot the mainstream in its upper reaches is NWW and is consistent with the regional structure line

but in its lower reaches the current direction of the mainstream is NS and is crossed with the regional structure line. 2. The growth of tributaries in the upper reaches is better than that in the lower reaches

where the pattern of drainage system is appeared as a poplar. 3. There is a fourth step of terrace belonged to the highest one of the region in the Jinqiang river basin of the upper reaches

but the terrace missed in the lower reaches.On the Landsat images

the auther further observed that both the Jinqiang Valley and the eastern adjacent Songshan sandbank are situated in the Jinqiang structure basin surrounded by mountains of geosynclinal fold. In fact

huth the fourth step of terrace in the Jinqiang Valley and the Songshan sandbank are the same level of landform

i.e. the top surface of the old accumulation in the Jinjiang structure basin. The Landsat image shows that the Jinqiang Valley cuts into this accumulation.It is believed that the features of the geomorphic growth of the Zhuanglang river basin are closely connected with the uplift of the Qinghai-Xizhang Plateau and are the result of the capture of the Jinqiang river by Zhuanglang river in the late Medial Pleistocene Epoch.