[Objective] The ecological environment of the Yarlung Zangbo River Basin is fragile. Revealing the spatiotemporal changes in the ecological service functions of the river basin and the trade-off and synergy of dominant functions can provide scientific and technological support for the ecological protection and restoration of the river basin. [Methods] Five critical ecosystem services (habitat quality, water production, soil conservation, carbon sequestration and food supply) were quantitatively assessed within Yarlung Zangbo River Basin using InVEST model. To analyze the spatiotemporal dynamics of ecosystem service functions across various altitudinal gradients and scales, and uncovers the tradeoffs and synergies among these services, Spearman non-parameter correlation analysis and geographical weighted analysis were employed. [Results] (1) From 2000 to 2020, the high values of five ecosystem services supply primarily concentrated in the lower reaches. The Yarlung Zangbo River Basin exhibited higher habitat q