A　numerical　and　experimental　study　of　heat　transfer　and　fluid　flow　in　plate　heat　exchanger　with　chevron　plates　has　been　presented　in　this　paper.　The　three-dimensional　geometry　without　any　simplification　is　modeled　by　software　SOLIDWORKS.　The　geometry　is　meshed　by　software　ICEM.　The　case　is　solved　by　software　FLUENT.　For　the　irregular　passage,　it　is　difficult　to　divide　the　zone　to　generate　grids　separately.　The　grid　must　be　generated　through　the　whole　zone　one　time.　A　tiny　clearance　between　two　plates　is　given　to　avoid　the　contact　points.　Two　types　of　plates　are　studied　to　validate　this　treatment.　we　compared　the　results　with　experiments.　Heat　transfer　and　pressure　drop　data　is　obtained　experimentally　with　water　as　the　working　fluid,　in　the　Reynolds　number　ranges　from　300-7000.　The　error　between　CFD＇s　and　experiments＇　results　in　no-phase　change　cases　can　be　controlled　in　±15%.　It　is　shown　that　the　tiny　clearance　treatment　is　effective　and　the　CFD　is　a　reliable　tool　for　studying　the　effect　of　various　geometrical　configurations　on　the　optimum　design　of　a　PHE.