Abstract: A preliminary investigation indicates that peatlands in Xizang plateau are mainly low and eutrophic herboceous peatlands,in which reserves of peat is nearly 170 million tons. Formation and evolution of peatlands was closely related to tectonic uplift of the plateau which resulted in climatic changes,regionaly active structure breaks and differential subsidence as Well. 1.The peatlands was mainly distributed at the altitute of 3600—4600m in the 28°—31°N,Lat.,which formed a long and narrow zone of 300km from the south to norh,and the width from East to west is 1200 kin. 2.At present,peatlands that formed in the periods of early and middle Holocene have been degenerated and shrunk,and there is a clear trend to meadow bogs or meadow.Developing peatlands were only distributed at the altitute of 3600—4200m in various valleies and basins,with an annual rainfall of 480—860mm;an accumulated tempeature(≥10℃) of 600—2000℃ and 100—150 days of which daily mean temperature is≥10℃. 3.Glacial meltwater is a main resource of water supply for the development of peatlands in the Xizang plateau. 4.There is a 30—60cm thick frozen soil layer at the depth of 60—100 cm below the surface of peatland,which is found at the altitute of 4000— 4600m near the line of 30°N,Lat.