A　LaFeO3　supported　Pd　nanoparticle　catalyst　Pd/LaFeO3　was　prepared　by　a　two-step　precipitation-deposition　method.　Its　catalytic　performance　for　the　reduction　of　NO　by　CO　was　subsequently　evaluated　in　the　lower　temperature　under　visible　light　irradiation　or　not.　It　was　found　that　visible　light　could　boost　the　progress　of　the　reaction　and　the　selectivity　of　forming　N-2.　The　results　of　temperature-programmed　desorption　(TPD)　of　CO　and　in-situ　diffuse　reflectance　infrared　Fourier　transform　spectra　(in-situ　DRIFTS)　showed　that　visible　light　could　enhance　the　adsorption　of　NO　and　its　activation　at　Pd　or　LaFeO3　site　and　that　of　CO　at　Pd　site,　respectively.　Co-adsorption　results　of　NO　+　CO　suggested　that　the　activated　intermediates　of　CO　and　NO　would　further　interact　to　form　the　isocyanate　(-NCO)　and　N2O　species,　which　finally　transformed　to　N-2　and　CO2.　Based　on　the　results　of　Raman　spectrum,　H-2-temperature　programmed　reduction　(TPR),　the　X-ray　photoelectron　spectroscopy　(XPS),　photoluminescence　spectra　(PL)　and　photocurrent　testing,　it　was　proposed　that　visible　light　irradiation　could　cause　the　increase　in　surface　electron　density　of　Pd　nanoparticles　by　the　photo-induced　electron　(from　O-2p　to　Fe-3d　orbit)　transfer　from　LaFeO3　to　Pd.　Moreover,　the　valence　exchange　of　Fe4+　and　Fe3+　induced　by　visible　light　could　promote　the　formation　of　oxygen　vacancies　and　then　the　adsorption　and　activation　of　CO　and　NO.　This　result　also　indicated　that　the　photo-excitation　of　supports　could　strengthen　the　strong　interaction　between　support　and　metal　nanoparticles,　and　then　promote　the　thermo-catalytic　reactivity　of　catalysts.