The work selected the nebkhas in the lower reaches of the Heihe River as the research object,using the ~(14)C to establish the time series of aeolian sand deposition and to analyze the climatic significance of geochemical elements and grain size of aeolian sand deposition as a substitute for environment. Through comprehensive analysis and regional comparison,the regional climate change in the last 300 years in this area has been carried on the preliminary discussion. The results show that the content of the constant element is characterized by the change of SiO_2 > Al_2O_3 > CaO > Fe_2O_3 > MgO > K_2O > Na_2O. The section in test site is located on climate and environment changes sensitive area,where aeolian sand depositions at least record 3 times relative drought period and 3 times the relative wet period. During the time,1823 years ago,1905 ~ 1929,1958 ~ 1973,the climate was in a cold dry period with the characteristics of relatively dry and cold. However,1824 ~ 1904,1930 ~ 1957, 1974,appearing the humid climate fluctuations,had been in a relatively warm period. Climate change in the lower reaches of the Heihe River had a good response to the surrounding and global climate change,and is an ideal place to study the modern climate change.