The topographic feature of Chengdu is that it inclines from northwest to southeast. Due to the huge vertical height difference, Chengdu has formed a unique landform type of one-third plain, one-third hill and one-third mountain. Due to the obvious climate differentiation, a vertical climate zone with obvious heat difference has been formed, so there are many kinds, complete categories and relatively concentrated distribution of biological resources in this area.
Chengdu is located in the western edge of Sichuan Basin, and its terrain inclines from northwest to southeast. The western part belongs to the marginal area of Sichuan basin, mainly in deep mountains and hills. Chengdu is mainly composed of plains, terraces and some low hills, with an altitude of 750 meters, and the lowest is on the bank of Tuojiang River in jianyang city, with an altitude of 359 meters.