The topography of China is complex and diverse, including plains, plateaus, mountains and hills. There are five kinds of landforms in the basin, and the mountainous area is vast, accounting for about 2/3 of the national area; The terrain is high in the west and low in the east, which is roughly distributed in three steps. The Qinghai-Tibet Plateau in the southwest, with an average elevation of more than 4,000 meters, is the first step. The west of the eastern line of Daxinganling-Taihang Mountain-Wushan-Yunnan-Guizhou Plateau and the first level are the second level, with an altitude of 1000m-2000m, which is mainly composed of plateaus and basins. East of the second step, the land surface above the horizon is the third step, which is below 500 meters above sea level, mainly hills and plains.
The complex and diverse terrain forms a complex and diverse climate; China's topography is high in the west and low in the east, which is ladder-shaped, which is conducive to the supply of deep moist air and a lot of water vapor; Make the river roll and flow, and communicate east-west traffic; The river flows from the higher steps to the lower steps, and the current is swift, generating huge water energy.
From west to east, there are the first, second and third steps in turn.