With average altitude 4000 meters, Tibet occupies most of the Qinghai-Tibet Plateau and is known as the "roof of the world". Tibet can be divided into three regions according to its topography: plateau in the north side, which consists of the Kunlun, Tanggula, Gangdise and Niangqingtanggula mountains, and occupies two thirds of the total area of the Tibet Autonomous Region, the valleys in the southern side, which lie between Gangdise and Himalayas and are crossed by Yarlung Zangbo River and its tributaries, the eastern area with high mountains and deep gorges, which belongs to part of the Hengduanshan Mountains.

With a total length of 2400 km, 200-300 km wide and 6000 m average altitude, Himalaya on the south side of the Qinghai Tibet Plateau are composed of many mountains running from east to west, the main part of which is located on the border at India and Nepal. The highest peak in the world, Qomolangma with 8844.43 m, lies in the central section of Himalaya on the border between China and Nepal. Nearby, there are four other peaks over 8,000 m high and 38 peaks over 7,000 m high.