Aluminum　and　aluminum　alloy　are　widely　used　in　every　field　of　modern　life.　It　is　especially　important　to　understand　the　detailed　mechanisms　of　aluminum　atmospheric　corrosion.　Traditional　studies　only　consider　the　role　of　oxygen　reduction　and　focus　on　anions　such　as　Cl-,　SO42-　in　the　environment,　ignoring　the　effects　of　cations　such　as　Na+　on　the　atmospheric　corrosion.　However,　recent　studies　have　shown　that　the　effect　of　Na　element　on　the　corrosion　of　aluminum　can　not　be　ignored.　In　this　work,　single-shot　laser-induced　breakdown　spectroscopy　(LIBS)　was　used　to　measure　the　aluminum　atomic　lines　after　corrosion　for　35　d　in　the　atmospheric　environment,　and　combined　with　a　three-dimensional　tomography　measurement,　to　study　the　depth　profiling　of　Na　on　the　aluminum　surface.　The　results　show　that　the　Na　element　on　the　surface　of　the　aluminum　originates　from　the　atmospheric　environment,　and　Na　is　involved　in　the　formation　of　corrosion　product　NaAlCO3(OH)(2).　The　content　of　NaAlCO3(OH)(2)　decreases　as　the　depth　increases　following　an　exponential　power　function.　The　content　decrease　of　NaAlCO3(OH)(2)　in　different　depths　can　be　transformed　into　the　change　of　cathode　area.　Combined　with　the　measured　polarization　curve　of　aluminum,　the　atmospheric　corrosion　model　of　aluminum　including　the　presence　of　oxygen　reduction　and　the　change　of　cathode　area　was　established　using　COMSOL　software.　The　calculated　corrosion　depth　is　6.155　mu　m,　which　is　consistent　with　the　depth　of　Na　element　measured　by　LIBS　experiments.　By　studying　the　distribution　of　Na　cations　and　corrosion　products,　a　simulation　model　was　established　to　reveal　the　influence　on　corrosion　mechanism,　which　is　of　great　significance　for　the　study　of　early　atmospheric　corrosion　of　aluminum.