The　turbulent　channel　flows　with　smooth　and　rough　walls　are　investigated　using　laser　Doppler　velocimeter　(LDV).　The　roughness　element　is　two-dimensional　spanwise　V-shape　groove,　and　the　depth　and　pitch　of　groove　is　0.8　mm　and　6.4　mm　respectively.　The　ratio　of　channel　half　height　to　groove　depth　is　12.5.　The　Reynolds　number　based　on　the　centerline　velocity　and　channel　half　height　is　varied　from　2740　to　17400.　The　measurements　involve　mean　velocity,　turbulence　intensity,　Reynolds　shear　stress　and　the　third　and　fourth　order　moments　of　velocity　fluctuation.　Results　show　that　the　effects　of　groove-shape　roughness　are　not　limited　in　the　inner　layer,　but　extend　to　the　whole　boundary　layer.　The　roughness　function　on　the　rough　wall　increases　with　the　Reynolds　number,　and　the　velocity　defect　profiles　are　slightly　higher　than　those　on　the　smooth　wall.　The　streamwise　turbulence　intensity　is　attenuated　significantly　in　the　inner　layer　and　meanwhile　is　intensified　slightly　in　the　outer　layer　by　the　grooves.　The　Reynolds　shear　stress　on　the　rough　wall　is　evidently　larger　than　that　on　the　smooth　wall.　Similar　to　the　turbulence　intensity,　the　Reynolds　shear　stress　profiles　on　the　smooth　and　rough　walls　both　exhibit　low-Reynolds-number　dependence.　The　skewness　of　streamwise　velocity　fluctuation　is　increased　by　the　groove-roughness,　although　the　flatness　is　hardly　affected　by　the　wall　conditions.