Abstract: As a typical closed lake in inland of arid area,Aiby lake has very sensitive response to the change of environment.The forming and evolution of Aiby lake are representative in arid area,therefore the study on forming and evolution of Aiby lake can reveals the environmental change in Aiby lake area during the geologic period.Based on the analysis of the sediment faces,granularity by Malvern2000laser granularity instrument, organic geochemical used analytical instrument of CHN in1.8m Ash core of Aiby lake southwest bottom,we rebuild the environment according different sediment era of Aiby lake with the ¹⁴C dating data.The results of this study indicate that as a whole the environment of Aiby lake area is comparatively stable in the past 3000years, but the water level of Aiby lake and the environment around the lake varied obviously mainly because of climatic vibration.During2600~2450a BP,the water level of the lake was low and the climate was cold and dry. Around2300a BP,the water level was lower than that of before.The river influenced the lake sharply.During 2300~440a BP,the water level became high ,the weather was warm and wet and the plants in land and water luxuriated.After440a BP,the Aiby lake got shallow.The climate became much more arid.As a typical closed lake in inland of arid area,Aiby lake has sensitive response to the change of globe environment.The forming and evolution of Aiby lake are representative in arid area.

Key words: Aiby Lake, grainsize characteristic, organic geochemical environmental evolution