N-Doped　KNbO3　(N-KNbO3)　was　prepared　through　mechanical　mixing,　grinding　and　calcination　of　urea　and　KNbO3.　The　photocatalytic　NO　oxidation　performance　was　evaluated　at　room　temperature　and　under　visible　light　irradiation.　Compared　with　the　pristine　KNbO3,　N-KNbO3　not　only　has　a　better　NO　oxidation　performance　but　also　can　effectively　inhibit　the　formation　of　NO2　(electron　paramagnetic　resonance).　EPR　tests　showed　that　the　doping　of　non-metallic　element　N　created　oxygen　vacancies　(OVs)　on　the　surface　of　KNbO3,　which　was　beneficial　to　the　formation　of　impurity　energy　levels　to　reduce　the　band　gap.　The　in　situ　diffuse　reflectance　infrared　Fourier　transform　spectroscopy　(DRIFTS)　results　indicated　that　NO　acquired　electrons　around　OVs　to　form　N2O2−　intermediates,　which　were　then　oxidized　by　reactive　oxygen　species　(OH,　O2−　and　1O2).　Moreover,　visible　light　can　promote　the　activation　of　NO　and　O2　and　also　the　formation　of　OVs.　This　work　provided　a　new　idea　for　the　design　and　preparation　of　N-doped　photocatalysts　for　NO　photocatalytic　oxidation.　©　2023　The　Royal　Society　of　Chemistry.