The Yellow River basin spans the Qinghai-Tibet Plateau, Inner Mongolia Plateau, Loess Plateau and Huanghuaihai Plain from west to east. The Yellow River, called China River in ancient times, originated from Bayan Kara Mountain Range in Qinghai Province, China, and flowed through nine provinces and regions, namely Qinghai, Sichuan, Gansu, Ningxia, Inner Mongolia, Shaanxi, Shanxi, Henan and Shandong, and finally merged into the Bohai Sea in Kenli County, Dongying City, Shandong Province.
The watershed between the Yangtze River Basin and the Yellow River Basin lies in the Qinling Mountains, especially in the broad sense. Qinling Mountains are divided into narrow Qinling Mountains and broad Qinling Mountains:
The narrow sense of Qinling Mountains is limited to the mountain range between Weihe River and Hanjiang River in southern Shaanxi Province, and it is the watershed of Jialing River, Luohe River, Weihe River and Hanjiang River. It is 400-500km long from east to west and100-150km wide from north to south.
The Qinling Mountains in a broad sense, which starts from Kunlun in the west, passes through Longnan and Shannan, and reaches Dabie Mountain in Hubei, Henan and Anhui and Zhangbaling near Bengbu in the east, is the watershed of the Yangtze River and Yellow River basins. The southern part of Qinling Mountain belongs to subtropical climate, and the natural conditions are southern type, while the northern part belongs to warm temperate climate and the natural conditions are northern type. Because of the different changes in temperature, climate, topography and agricultural production in the north and south of the Qinling Mountains, people have long regarded the Qinling Mountains as the geographical dividing line between the "south" and the "north" of China.