Kundulun River flows from east to west in the north of Chengguan Town, Guyang County, and from north to south in the south. Flowing out of the mountain area and entering the plain area in front of Xincheng Township in Qingshan District. The southern section of this valley is a throat passage through Yinshan Mountain in ancient and modern times. The river is a seasonal river with frequent floods. Most of the river basins are rocky mountainous areas, with sparse vegetation on slopes and serious soil erosion.
Kundulun Valley is flat and the carriage is feasible, which is the most ideal road for smooth traffic across Yinshan Mountain. As early as the pre-Qin period, Gu Dao was developed and formed. Because it is in the middle of three roads leading to Mobei in traffic geography, it was once called the middle road. From the Han Dynasty to the Northern Wei Dynasty, it was also called "Yang Dao". Historically, it has played a great role in the communication between nomadic people in Mongolian grassland and farming people in the Yellow River basin.