Using X-ray fluorescence scanning and AMS ¹⁴C analyses, we present a geochemical record of a 4.56 m long sediment core from Yilong Lake, Yunnan Province, southwestern China. Factor analysis of the geochemical elements revealed three factors, F1, F2, and F3. F1 indicates the sources of sedimentary geochemical elements, with its positive loads relating to the increased input of exogenous materials and negative loads showing increased authigenic carbonate precipitation. F2 indicates a lacustrine redox state. F3 is probably relating to human activities. Here, we discuss the process of climate and environmental changes, based on variations in the geochemical records, as well as the magnetic susceptibility, mineral compositions and organic contents. During Last Glacial Maximum, from 26,000 to 17,000 cal. yr. BP, a relatively cold and dry climate dominated this region. The climate trended to be drier, probably in relation to the rapid decrease in monsoonal precipitation from 17,000 to 14,500 cal. yr. BP. After 14,500 cal. yr. BP, the water level in Yilong Lake rose, lasting until 9000 cal. yr. BP. This high lake level was consistent with that of Dianchi Lake, indicating a regional humid condition in response to an increase in monsoonal precipitation. From 9,000 to 6,000 cal. yr. BP, the regional temperature increased in response to the Holocene Megathermal Maximum. After 6,000 cal. yr. BP, a decreased in exogenous materials indicates that the regional precipitation probably decreased. Although the hydroclimate evolution of Yilong Lake is consistent with the effects of regional climate change, it is also with obvious particularity, and more studies are needed to gain a comprehensive understanding of the regional historic environment change.