Mg-doped　ZnO(MZO)　nanorod　arrays　were　fabricated　by　hydrothermal　method　in　the　mixed　solution　of　Zn(NO3)2·6H2O　and　Mg(NO3)2·6H2O　with　Mg2+　concentrations　varying　from　0.05　mol/L,　0.10　mol/L,　0.25　mol/L　to　0.50　mol/L.　The　morphology　and　composition　of　MZO　arrays　were　characterized　by　field　emission　scanning　electron　microscopy(FESEM)　and　X-ray　photoelectron　spectroscopy　(XPS),　respectively.　The　effects　of　Mg　dopants　on　the　crystal　structures　and　optical　properties　were　investigated　by　using　X-ray　diffraction(XRD)　and　photoluminescence(PL),　then　their　field　emission　properties　were　also　evaluated.　Results　show　that　higher　doping　led　to　the　formation　of　nanorod　arrays　with　smaller　diameters　and　more　defects,　but　the　higher　c(Mg2+)in　solution　did　not　induce　higher　Mg　doping.　The　best　field　emission　performance　of　the　MZO　nanorod　arrays　was　synthesized　in　0.　10　mol/L　c(Mg2+)　solution,　which　had　a　low　turn-on　field　of　2.85　V/μm.　©,　2014,　Tianjin　University.　All　right　reserved.