With　semiconductor　processes　advancing,　integrated　circuits　have　moved　further　along　the　Moore＇s　Law　[1].　Meanwhile,　chip　integration　and　power　density　increased　substantially,　making　thermal　problems　more　serious　[2].　In　this　circumstance,　researchers　have　conducted　a　large　number　of　experiments　on　fluid　flow　and　heat　transfer　in　microchannels,　to　improve　cooling　performance.　In　the　early　days,　microchannel　heat　dissipation　technique　was　mostly　achieved　by　etching　microchannels　on　silicon　wafers.　There　is　no　doubt　that　diamond　has　a　thermal　conductivity　one　magnitude　higher　than　silicon.　So　diamond　can　improve　the　heat　dissipation　performance　of　the　heat　sink.　Due　to　diamond　etching　technology　has　been　developed,　the　use　of　diamond　as　a　material　for　heat　sinks　has　received　extensive　attention.　In　this　paper,　finite　element　simulation　is　used　to　study　thermal　property　of　diamond　heat　sink.　The　microchannel　heat　sink　is　fabricated　by　bonding　a　diamond　wafer　and　a　silicon　wafer.　Temperature　rise　is　the　objective　function　to　be　minimized　with　height　of　microchannels　(H-c),　number　of　microchannels　(N),　and　the　duty　ratio　of　microchannel　(alpha),　as　optimize　variables.　Depending　on　the　experimental　results,　combined　with　the　actual　feasibility,　the　best　result　is　that　the　flow　path　height　is　250　mu　m,　the　duty　ratio　is　0.7,　and　the　number　of　flow　channels　is　60.　Under　this　condition,　the　temperature　rise　is　30　degrees　C.