We　have　investigated　the　reaction　mechanism　for　N2O　decomposition　on　Cu-13　via　density　functional　theory.　It　is　found　that　N2O　decomposition　on　the　cluster　is　more　prone　to　be　along　the　Eley-Rideal　(ER)　pathway　in　comparison　with　the　Langmuir-Hinshelwood　(LH)　channel.　There　exists　structural　relaxation　for　Cu-13　cluster　in　the　reaction,　which　may　influence　the　catalytic　activity　of　cluster　for　the　subsequent　N2O　decomposition.　The　core　atom　in　the　Cu-13　cluster　is　substituted　with　the　Fe,　Co,　or　Ni　to　enhance　structural　stability　and　prevent　from　the　obvious　configuration　relaxation　in　the　reaction.　Note　that　these　bimetallic　clusters　are　of　icosahedra　as　the　Cu-13.　They　have　activities　for　N2O　dissociation　along　ER　pathway　and　the　heteroatom　in　the　cluster　can　prevent　configuration　from　relaxation.　Finally,　the　Ni@Cu-12　cluster　can　be　as　a　superior　catalyst　in　a　complete　catalytic　cycle　via　comparison　in　this　study.