In　this　work,　a　room-temperature　NO2　gas　sensor　based　on　Au-functionalized　CuO　nanorods　(Au-CNRs)　via　a　facile　one-pot　hydrothermal　route　was　fabricated.　The　material　characterizations　were　studied　by　XRD,　SEM,　TEM,　XPS,　and　FTIR,　respectively.　The　diameter　and　length　of　the　pristine　CuO　nanorods　(CNRs)　were　30-60　nm　and　150-200　nm,　respectively.　The　CNRs　structure　was　not　significantly　affected　by　Au　functionalization.　Au　nanoparticles　with　the　diameters　of　less　than　20　nm　were　uniformly　distributed　on　the　surface　of　2　mol%　Au-CNRs.　The　gas　sensing　test　result　showed　that　room-temperature　NO2　sensing　can　be　achieved　by　Au-functionalized　CuO　nanorods,　especially　the　2　mol%　Au-CNRs,　which　exhibited　the　response　of　3　towards　20　ppm　NO2　with　the　response　and　recovery　times　of　8　s　and　176　s　at　room　temperature　(25　degrees　C).　This　sample　also　showed　good　selectivity　and　reproducibility　to　NO2.　The　related　sensing　mechanism　of　the　CNRs　based　materials　to　NO2　was　investigated　by　the　changing　of　energy　band　gap　and　activation　energy　with　Au　functionalization,　respectively.