Grain-size evolution characteristics and their environmental significance of Hulun Lake sediments were investigated since 1865 to 2016.The sediment core with a length of 78 cm was collected in the center of the lake in August 2016.Mechanical compositions of grain-size and frequency distribution curves were measured by the grain-size analyzerMastersizer 2000.Based on accurate dating by 210Pb,the regional environment and climate changes of the Hulun Lake according to the vertical profile of sediment grain sizes,which provides a new effective way for recovering the century-scale climatic changes.The results indicate that:sediments were mainly composed of silt and clay,and significant positive correlation were found between the contents of median grain-size and coarse silt and sand.Contents of median grain-size showed the changes of decrease,fluctuation and increase from the bottom to top of the sediment core.Three environmental sensitive components of atmospheric dust,eulimnetic facies,dust storm were identified by the method of log-normal distribution.Good agreements were found among the changes of grain-size,sensitive components,lake water levels,precipitations,and dust events.The results indicated that the current study well reconstructed the history of dry and wet climatic changes and wind-sand activities characteristics.