Abstract: The vegetation in Chaidar valley of Tsinghai province has been classified into alpine steppe, alpine meadow, alpine scrub, swamp meadow and alluvial flat meadow. It is used as a indicator to distinguish the frozen soil. Seasonal frozen soil is usually distributed in alpine steppe. Local appearance of swamp meadow and perennial frozen soil as island is due to the influence of ground water. The perennial frozen soil is mainly distributed in the alpine meadow and alpine scrub. The alluvial flat meadow and seasonal frozen soil are distributed as island or strap along the river due to the influence of water flow. Finelly, their relationships are shown in the key to be used as a reference for related research workers.