This study aims to comprehensively analyze the spatial extent, extinction time, and causes of the Chengchuan Paleolake in the southern Mu Us Desert by integrating multi- source evidence.Methods: Integrated field investigations, remote sensing imagery interpretation, chronological analysis of Holocene lacustrine strata, and synthesis of historical literature documenting regional lake evolution were employed.Results: The Chengchuan Paleolake covered ~130 km2, significantly exceeding prior estimates of 100 km2, as constrained by newly identified sedimentary boundaries and topographic data. Its extinction occurred around 300 a AD, synchronous with climatic cooling and aridification trends across China and the Northern Hemisphere. Despite subsequent temperature increases, the lake never recovered due to neotectonic uplift post- 300 a AD along its eastern margin. This uplift initiated the formation of the Salawusu River Valley, diverting groundwater and disrupting hydrological stability. Concurrently, human activities modified impermeable Holocene lacustrine deposits, creating artificial drainage systems that accelerated surface water loss into the Salawusu and Wuding Rivers, ultimately integrating the paleolake into the Yellow River system.Conclusions:The permanent extinction of Chengchuan Paleolake resulted from synergistic drivers: Initial climate- driven aridification triggered decline (~300 a AD); neotectonic uplift established irreversible drainage pathways; and anthropogenic alterations further disrupted hydrology, transforming the basin into part of the Yellow River network.