The　surface　reconstruction　of　oxygen　evolution　reaction　(OER)　catalysts　has　been　proven　favorable　for　enhancing　its　catalytic　activity.　However,　what　is　the　active　site　and　how　to　promote　the　active　species　generation　remain　unclear　and　are　still　under　debate.　Here,　the　in　situ　synthesis　of　CoNi　incorporated　Fe3N　nanotubes　(CoNi-Fe3N)　on　the　iron　foil　through　the　anodization/electrodeposition/nitridation　process　for　use　of　boosted　OER　catalysis　is　reported.　The　synergistic　CoNi　doping　induces　the　lattice　expansion　and　up　shifts　the　d-band　center　of　Fe3N,　which　enhances　the　adsorption　of　hydroxyl　groups　from　electrolyte　during　the　OER　catalysis,　facilitating　the　generation　of　active　CoNi-FeOOH　on　the　Fe3N　nanotube　surface.　As　a　result　of　this　OER-conditioned　surface　reconstruction,　the　optimized　catalyst　requires　an　overpotential　of　only　285　mV　at　a　current　density　of　10　mA　cm(-2)with　a　Tafel　slope　of　34　mV　dec(-1),　outperforming　commercial　RuO(2)catalysts.　Density　functional　theory　(DFT)　calculations　further　reveal　that　the　Ni　site　in　CoNi-FeOOH　modulates　the　adsorption　of　OER　intermediates　and　delivers　a　lower　overpotential　than　those　from　Fe　and　Co　sites,　serving　as　the　optimal　active　site　for　excellent　OER　performance.