The　stability　of　future　carbon　sinks　is　crucial　for　accurately　predicting　the　global　carbon　cycle.　However,　the　future　dynamics　and　stability　of　carbon　sinks　remain　largely　unknown,　especially　in　China,　a　significant　global　carbon　sink　region.　Here,　we　examined　the　dynamics　and　stability　of　carbon　sinks　in　China’s　terrestrial　ecosystems　from　2015　to　2,100　under　two　CMIP6　scenarios　(SSP245　and　SSP585),　using　XGBoost　and　SHAP　models　to　quantify　the　impact　of　climatic　drivers　on　carbon　sink　stability.　China’s　future　terrestrial　ecosystems　will　act　as　a　“carbon　sink”　(0.27–0.33　PgC/yr),　with　an　initial　increase　that　levels　off　over　time.　Although　the　carbon　sink　capacity　increases,　its　stability　does　not　consistently　improve.　Specifically,　the　stability　of　carbon　sinks　in　future　China’s　terrestrial　ecosystems　transitions　from　strengthening　to　weakening,　primarily　occurring　in　areas　with　higher　carbon　sink　capacity.　Further　analysis　revealed　that　atmospheric　vapor　pressure　deficit　(VPD)　and　temperature　(Tas)　are　the　two　primary　factors　influencing　carbon　sink　stability,　with　significant　differences　in　their　impacts　across　different　scenarios.　Under　the　SSP245　scenario,　variations　in　VPD　(VPD.CV)　regulate　water　availability　through　stomatal　conductance,　making　it　the　key　driver　of　changes　in　carbon　sink　stability.　In　contrast,　under　the　SSP585　scenario,　although　VPD.CV　still　plays　an　important　role,　temperature　variability　(Tas.CV)　becomes　the　dominant　factor,　with　more　frequent　extreme　climate　events　exacerbating　carbon　cycle　instability.　The　study　highlights　the　differences　in　driving　factors　of　carbon　sink　stability　under　different　scenarios　and　stresses　the　importance　of　considering　these　differences,　along　with　the　scale　and　stability　of　carbon　sinks,　when　developing　long-term　carbon　management　policies　to　effectively　support　carbon　neutrality　goals.　Copyright　©　2024　Zhou,　Ren,　Shi,　He,　Zhang,　Wang,　Zhang,　Zhang　and　Fan.