In　this　paper,　the　study　on　the　flow　and　heat　transfer　characteristics　of　the　rib-grooved　channel　is　conducted.　In　detailed,　the　effect　of　the　spanwise　distribution　of　the　rib　height　on　the　thermal　performance　of　the　channel　is　investigated.　In　this　work,　five　ribs　with　different　spanwise　distributed　height　have　the　same　cross-section　area.　The　rib　middle　height　increases　as　the　case　ID　increases　from　1　to　5,　and　the　rib　of　case3　has　the　uniform　spanwise　distributed　height.　The　results　indicate　that　ribs　with　uneven　spanwise　distributed　height　induce　the　counter-rotating　vortex　pair　which　transports　the　core　cooler　flow　to　the　near　wall　region　and　washes　up　the　hotter　air　trapped　inside　the　groove,　and　this　thus　causes　an　increase　in　the　near-wall　velocity　and　correspondingly　enhances　the　heat　transfer　performance　of　the　heated　wall.　In　addition,　the　higher　variation　in　the　rib　height　along　spanwise　direction　causes　the　stronger　vortex　structure　which　leads　to　the　higher　heat　transfer　rate.　The　case　of　rib　with　the　highest　middle　height　provides　the　highest　Nusselt　number,　friction　factor　and　thermal　performance　factor.　©　2017,　Science　Press.　All　right　reserved.