We　investigated　the　spoof　surface　plasmon　polaritons　(SSPPs)　on　1D　grooved　metal　surface　for　terahertz　sensing　of　refractive　index　of　the　filling　analyte　through　a　prism-coupling　attenuated　total　reflection　setup.　From　the　dispersion　relation　analysis　and　the　finite　element　method-based　simulation,　we　revealed　that　the　dispersion　curve　of　SSPP　got　suppressed　as　the　filling　refractive　index　increased,　which　cause　the　coupling　resonance　frequency　redshifting　in　the　reflection　spectrum.　The　simulated　results　for　testing　various　refractive　indexes　demonstrated　that　the　incident　angle　of　terahertz　radiation　has　a　great　effect　on　the　performance　of　sensing.　Smaller　incident　angle　will　result　in　a　higher　sensitive　sensing　with　a　narrower　detection　range.　In　the　meanwhile,　the　higher　order　mode　SSPP-based　sensing　has　a　higher　sensitivity　with　a　narrower　detection　range.　The　maximum　sensitivity　is　2.57　THz/RIU　for　the　second-order　mode　sensing　at　45　degrees　internal　incident　angle.　The　proposed　SSPP-based　method　has　great　potential　for　high　sensitive　terahertz　sensing.　(C)　2015　AIP　Publishing　LLC.