According　to　the　mixing　principle　of　Tesla-type　micromixer,　Three-dimensional　numerical　simulation　was　carried　out　with　adoption　of　Computational　Fluid　Dynamic　software　in　this　paper.　The　nite　volume　method　was　used　to　disperse　the　three-dimensional　steady　incompressible　N-S　equations.　The　effect　of　mixing　performance　was　analyzed　when　changing　the　structural　parameters　of　this　type　micromixer.　Mixing　index　is　measure　standard　used　to　evaluate　the　degree　of　mixing.　Our　studies　show　that　the　structural　parameters,　e.g.　different　aspect　ratio　of　microchannels　and　the　inflow　angle　of　separation　channel,　have　an　important　effect　on　the　mixing　performance.　Taking　account　for　the　relation　between　mixing　intensity　and　pump　power　consumption,　the　optimum　structure　parameters　of　Tesla-type　micromixer　are　B/W=0.75　and　α=55°.