Abstract: Terrestrial water storage is the comprehensive reflection of precipitation, evapotranspiration, runoff, infiltration and other hydrological processes, it controls hydrological cycle processes at different scales. Analyzing the long-term changes of terrestrial water storage in the Qinghai-Tibetan Plateau and clarifying the impact of climate change can cause a scientific understanding of current water security risks and improve water resource managements in the Qinghai-Tibetan Plateau. This study utilizes the GRACE data and ISI-MIP2b simulations, combing multi-model weighing method with Mann-Kendall trend analysis to analyze the temporal and spatial changes of terrestrial water storage in the Qinghai-Tibetan Plateau during 1861-2005 and 2006-2099. Further, it investigates the impact of climate change on terrestrial water and groundwater storage through different scenarios. This study finds that:（1） The GRACE data showed that the terrestrial water storage in the Qinghai-Tibetan Plateau presented a decreasing trend from 2002 to 2017, and the spatial heterogeneity of water storage changing is strong. The southern part of the plateau showed a decreasing trend and the northern part showed an increasing trend.（2） The ISI-MIP2b multi-model simulations showed that the terrestrial water storage in the Qinghai-Tibetan Plateau during 1861-2005 exhibiting increasing trends（P＜0.01） under picontrol scenario（PIC） and historical scenario（HIST）. Climate change reduced the increase rate of terrestrial water storage（0.50 km3/a）. In addition, the terrestrial water storage in most parts of the eastern and central of the plateau changed from an increasing trend to a decreasing trend under the PIC scenario due to climate change.（3） From 2006 to 2099, the trend of terrestrial water storage changed from an increasing to decreasing trend due to climate change. Terrestrial water storage showed an increasing trend under PIC scenario, while it showed decreasing trends under RCP2.6, RCP6.0 and RCP8.5 scenarios. Terrestrial water storage in most parts of the ThreeRivers Headwaters Region showed decreasing trends under the four scenarios, while it showed an increasing trend in the inner river basins under RCP2.6, RCP6.0 and RCP8.5 scenarios. The groundwater storage showed a decreasing trend under PIC scenario while it showed an increasing trend under other scenarios, and the higher radiation forcing scenario showed a higher increase rate.