Since the 1950s, many lakes in Yunnan have been directly impacted by watershed development activities such as hydrological regulation (such as damming) and fish introduction, and thus lake environment and ecosystem structure have changed significantly. Investigation on the long-term response of zooplankton communities to limnological changes is vital for understanding the effects of climate change and anthropogenic stresses on lakes. In this study, Lake Tianchi from Yunlong County, northwest Yunnan, was selected for reconstructing environmental change history over the past 100 years, with a focus on the succession of the cladoceran community and the identification of its environmental drivers. The results showed that Lake Tianchi has experienced significant fluctuations in water level over the past 100 years, which was relatively low before about 1962, gradually rose during 1962-2006 due to hydrological regulation (damming), and slightly declined from about 2006 onward. The dominant taxa of cladoceran community shifted from littoral species to planktonic ones while benthic taxa slightly increased after 2006. In brief, benthic cladocerans were generally dominant during the low water-level period, while planktonic taxa predominated when water level rose. The percentage of Bosmina longirostris and the cladoceran concentration were both increased when the sedimentary TN and LOI₅₅₀ increased since the 1960s, suggesting that the influence of nutrients on the compositional change and production of cladocerans. After planktivorous fish was introduced in 1969, the carapace, carapace mucro and antennule lengths of Bosmina were all significantly decreased, suggesting the influence of increasing predation pressure by zooplanktivorous fish. This study highlights the long-term impacts of hydrological regulation and fish introduction on the lake environment and biological community structure. Before the 1960s, the lake was generally in natural conditions, lake environment and cladoceran communities were mainly affected by climate (precipitation, temperature), while, after the 1960s, the influence of human activities has overridden the role of climate change and become the main factor in affecting the ecological structure of Lake Tianchi. For lake protection and ecological remediation, it is necessary to comprehensively assess the impact of multiple human activities (i.e. hydrological regulation and fish introduction) on lake ecosystem health for generating appropriate restoration strategies.