A　theoretical　study　was　carried　out　on　the　adsorption　of　hydrocyanic　acid　on　small　Au-n　(n　＜=　7)　clusters　using　density　functional　methods.　For　HCN　adsorption　on　gold　clusters,　no　dependence　was　found　with　respect　to　the　even-odd　alternation　in　relation　to　the　number　of　gold　atoms　in　the　cluster.　The　HCN　molecule　is　adsorbed　at　simple　adsorption　sites　(I-fold　coordination),　perpendicular　to　the　adsorption　site.　The　largest　adsorption　energy　is　only　about　74.61　kJ.mol(-1),　which　indicates　that　the　HCN　molecule　does　not　decompose　and　the　C-N　bond　retains　triple　bond,　and　that　the　C-H　and　C-N　stretching　frequencies　are　only　weakly　perturbed.　The　adsorbed　C-N　and　C-H　stretching　frequencies　are　blue-　and　red-shifted　compared　with　the　values　of　free　HCN,　respectively.