Abstract： Based on global comparison of geological records, the international Anthropocene Working Group (AWG) suggested that the mid-20th century (~1950 CE) be the onset of the Anthropocene, the Sihailongwan maar Lake sediment had been listed as one of the candidates for Global Stratotype Section and Point (GSSP) for Anthropocene. However, human had put a profound impact on the environment of areas around the Sihailongwan maar Lake before 1950 CE. Historical sequences of TOC contents, C/N ratios, δ¹³C_org values, Ca/Ti ratios and concentrations of silicate major elements Si, Al, K since 900 CE were reconstructed, the average resolution is ~10 a, to explore the history of human activities in this region, with the background of climate change. It was found that human activities had significantly increased since 1850 CE, but the changes in the measured proxies during the Medieval Warm Period and Little Ice Age before 1850 CE generally followed natural laws. The changes in the measured proxies during 1850–1950 CE reflected the rapid population growth, which damaged vegetation, and thus resulted in intensified weathering, and deviation of the surface environment evolution from natural state, these indicate that human had started to be an important force for geological environment, but the changes during this period were only local signals; after 1950 CE, C/N ratios and δ¹³C_org values decreased continuously, which reflected that the environmental status of the area around Sihailongwan maar Lake changed once again, under the new government and advanced productivity, this was in sync with the Great Acceleration of global geological environment, and can support that “the mid-20th century is the onset time of the Anthropocene” proposed by the AWG.