Triangular gold nanoprisms with high yield percentage were synthesized via the seed-mediated approach and functionalized by mono-6-thio-β-cyclodextrin without alkyl chain. The undecorated and decorated triangular gold nanoprisms were characterized and analyzed. Moreover, the novel decorated triangular gold nanoprisms were used as surface-enhanced Raman spectroscopy (SERS) substrates for chemical sensing of the explosive agent 2,4-dinitrotoluene (DNT). The vibrational bands in the experimental SERS spectrum were assigned with the aid of density functional theoretical simulation. The analytical enhancement factor of the hybridized triangular gold nanoprisms for the detection of DNT has been obviously increased in contrast with hybridized spherical gold nanoparticles, suggesting that the former are excellent SERS substrates. Compared to some other approaches, the limit of detection can be remarkably improved (qualified as sub-ppb level), which indicates that the excellent chemical sensing of decorated triangular gold nanoprisms can be widely applied to trace analysis of explosive or warfare agents. Copyright © 2011 John Wiley & Sons, Ltd.