Abstract: In recent years, the water level of Fuxian Lake has decreased seriously.It is of great significance to study the characteristics and influencing factors of water level change for maintaining the stability of the lake ecosystem.The Mann-Kendall trend test, cumulative anomaly test, and Pettitt mutation test were used to analyze the inter-annual and intra-annual variation patterns of water level.The water balance method was used to analyze the changes in lake water, and the slope change ratio of cumulative quantity(SCRCQ) method was used to investigate the effects of climate change and human activities on the runoff of the Fuxian Lake basin from 1953 to 2020.The findings indicated that:(1) The interannual water level of Fuxian Lake displayed a rising-declining-rising-declining pattern from 1953 to 2020,with seasonal fluctuations typified by the high water level in the fall and low water level in the summer.(2) In comparison to the baseline period of 1962～1974,the contribution rates of climate change and human activities to runoff were 10.0% and 90.0% during 1975～2008,and 18.1% and 81.9% during 2009～2020.The contribution rate of human activities played a dominant role but decreased somewhat in recent years.The reduction of the human activities' contribution rate to runoff was related to managing water abstraction permits in the Fuxian Lake basin, relocating industrial parks, and operating water diversion projects.Reducing the influence of human activities could be beneficial to ensuring the stability of Fuxian Lake's water level.