Heat　transfer　can　be　enhanced　by　longitudinal　vortex　in　narrow　rectangular　channels.　Thermal　infrared　imager　has　been　used　to　measure　the　temperature　field　of　heated　plate　with　4　pairs　rectangular　block　longitudinal　vortex　generators　and　smooth　heated　plate.　The　experimental　results　showed　that　the　average　value　of　inside　wall　temperature　can　be　decreased　by　18.1%　or　the　heated　power　can　be　increased　by　29.3%.