Cyclic　voltammetric　and　chronoamperometric　methods　were　used　to　study　the　initial　stage　of　Au　electrodeposition　on　an　indium　tin　oxide　(ITO)　surface.　The　nucleation　process　was　controlled　by　the　diffusion　of　[AuCl4]-.　The　cyclic　voltammetry　curves　showed　that　the　electrochemical　reduction　included　two　steps　which　were　[AuCl4]-→　[AuCl2]-,　and　[AuCl2]-　→　Au.　Only　one　reduction　peak　was　observed　when　the　scan　rate　was　comparatively　slow　and　this　peak　separated　into　two　peaks　when　the　scan　rate　was　increased.　This　phenomenon　resulted　from　the　disproportionation　of　[AuCl2]-　during　the　electrodeposition　process.　Chronoamperometry　also　proved　the　two　step　reaction　mechanism　and　the　diffusion　coefficient　of　[AuCl4]-　was　calculated　to　be　1.3×10-5　cm2·s-1.　From　the　theoretical　nucleation　curves,　an　instantaneous　three-dimensional　nucleation　mechanism　was　proposed　for　the　nucleation　of　gold　on　ITO.　Au　electrodeposits　were　observed　by　field　emission　scanning　electron　microscopy　(FE-SEM).　SEM　images　of　the　electrodeposits　showed　that　the　morphology　of　the　gold　deposits　was　affected　by　the　electrochemical　deposition　potential　and　time.　©　Editorial　office　of　Acta　Physico-Chimica　Sinica.