The　structural　stability,　electronic　and　catalytic　properties　of　Aun　(n　=　1-4)　nanoclusters　supported　on　monolayer　MoS2　have　been　investigated　based　on　first　principle　DFT　calculation　with　van　der　Waals　(vdW)　corrections.　Our　results　show　that　all　Aun　(n　=　1-4)　nanoclusters　prefer　to　bind　vertically　on　the　top　S　sites　of　the　monolayer　MoS2.　And　the　relative　stability　of　Aun　(n　=　1-4)　clusters　in　gas　phase　is　not　preserved　after　landing　on　monolayer　MoS2.　By　including　van　der　Waals　(vdW)　corrections　with　different　approaches,　we　found　that　the　van　der　Waals　correction　increased　the　adsorption　energies　for　all　supported　Aun　(n　=　1-4)　clusters　with　the　order　of　Eads(PBE-D2)　>　Eads(PBE-D3)　>　Eads(optB86b-vdW)　>　Eads(PBE).　And　the　van　der　Waals　effects　can　also　change　the　order　of　stability　and　the　energy　differences　of　various　deposition　configurations.　In　addition,　the　binding　of　O2　is　also　modeled,　showing　significantly　enhanced　adsorption　properties　and　catalytic　activation　toward　O2　adsorption,　especially　for　that　on　supported　Au1　and　Au3　clusters　with　magnetic　properties,　with　respect　to　that　on　supported　Au2　and　Au4　clusters　with　nonmagnetic　properties.　The　current　study　provides　further　insight　into　the　adsorption　and　catalytic　properties　of　small　gold　clusters　supported　on　monolayer　MoS2,　which　play　a　crucial　role　in　the　activation　of　O2.　©　2017　The　Royal　Society　of　Chemistry.