Previous　studies　have　shown　some　correlations　between　the　optical　properties　of　objects　and　their　surface　patterns.　We　fabricate　tens　of　micrometer　period　gratings　by　femtosecond　laser　direct　writing　technology　on　polished　nickel　targets　and　measure　their　thermal　radiation　spectra　at　a　temperature　of　623　K　by　Fourier　transform　infrared　(FTIR)　spectrometry.　The　results　show　an　obvious　major　enhanced　peak　in　which　the　wavelength　is　slightly　larger　than　the　grating　period.　Surface　plasmon　resonance　(SPR)　and　Kirchhoff＇s　law　of　thermal　radiation　are　applied　to　give　this　phenomenon　a　preliminary　explanation.　In　addition,　we　utilized　rigorous　coupled　wave　analysis　(RCWA)　to　simulate　the　absorption　spectrum　of　the　grating　surface.　The　experiment　results　show　good　agreement　with　the　simulation　results.