The　electronic　and　geometric　robustness　of　active　sites　in　catalysts　determines　their　long-term　efficiency　in　CO2　hydrogenation.　One　effective　strategy　to　improve　durability　is　rationalizing　metal　site　charge　distribution　through　strong　metal-support　interactions　(SMSIs).　We　propose　an　effective　approach　that　can　modulate　the　SMSI　between　Pd　and　CeO2　by　doping　chlorine　anions　into　the　CeO2　lattice.　The　developed　Pd@CeOCl/CeO2　catalyst　exhibits　sustainable　activity　(3150　mmol·gPd-1·h-1)　and　CO　selectivity　(99.7%)　for　at　least　200　h,　as　well　as　enhanced　resistance　toward　CO　and　H2O.　Anion-doping-mediated　SMSIs　result　in　significant　electronic　perturbations　in　the　Pdδ+-[Cl-Ce-O]δ−　interface,　which　modulates　the　surface　properties　and　the　energy　band　of　the　catalyst.　Combined　spectroscopic　and　microscopic　evidence　unveils　that　a　Clδ−-Cl-　pair　buffers　the　electron　transfer　in　Pdδ+↔Pd0　and　Ce4+↔Ce3+　cycles,　which　circumvents　the　further　hydrogenation　of　CO　and　shields　Pdδ+　sites　from　sintering　in　hydrogenation　conditions.　©　2024　American　Chemical　Society.