The　dissociation　of　water　is　essential　to　water　gas　shift　(WGS)　reaction,　and　the　presence　of　oxygen　vacancies　can　facilitate　this　key　step.　Herein,　a　series　of　perovskite　supported　Pd　single　atoms　catalysts　were　prepared　via　deposition　precipitation　method.　The　incorporation　of　Pd　single　atoms　can　effectively　promote　the　formation　of　oxygen　vacancy　on　the　surface　of　the　catalyst,　improving　the　low　temperature　reducibility,　the　ratio　of　Mn4+　/　Mn3+　and　O-ads/O-lat　compared　with　support.　Among　all　samples,　0.82　Pd/La0.5Ca0.5MnO3/SBA-15　with　the　most　oxygen　vacancies　presented　83.6　%　CO　conversion　at　400　degrees　C,　specific　reaction　rate　(0.54　mol(CO)　g(Pd)(-1)　h(-1)　),　and　TOF　(3.77.10(-2)　s(-1)).　DFT　calculation　proved　that　Pd　doping　can　effectively　decreased　energy　barrier　of　H2O　dissociation,　and　promoted　the　formation　of　oxygen　vacancies.　This　work　provides　experimental　and　theoretical　insights　into　the　rational　design　of　highly　active　perovskite　supported　Pd　single　atom　catalysts　for　WGS　reaction.