An 80-cm-long sedimentary core from Lake Jili, which lies in westerly area of China, provided detailed informationabout paleoclimatic and paleoenvironmental changes in the past 2500 years. The temporal sequence of sedimentary core was con-structed using the ²¹⁰Pb,¹³⁷Cs and AMS ¹⁴C dating methods on the bulk organic matter. Based on analyses of grain-size, total or-ganic carbon, total nitrogen and organic carbon isotope, climatic and environmental evolution history in the past 2500 years was re-constructed. The sequence of climatic changes in the region since 2. 5ka BP was established. The climatic changes experienced fivestages; warm-wet climate during 500BC-50BC; cold-wet climate during $OBC-650AD; warm-dry climate during 650-1350ADwarm period(MWP);cold-dry climate period during 1350-1850 AD (LIA),and moderate-dry since 1850AD, including climatewarming after 1920x, especially since 1970x. The records of climatic and environmental evolution of Lake Jili were in good accord-ing with the historical literature records and other geologic records of adjacent areas.