Qinghai-Tibet Plateau is the largest plateau in China and the highest in the world. It is called the "Roof of the World" and "the Third Pole". It rises from the southern margin of the Himalayas in the south to the northern margin of Kunlun, Altun and Qilian Mountains in the north, from the Pamir Plateau and the Karakoram Mountains in the west, from the East and northeast to the western part of the Qinling Mountains and from the Loess Plateau in the north. The original connection is between 26 degrees north latitude, 00 degree to 39 degree 47 ', and 73 degrees 19' - 104 degrees 47 'east longitude.