In　order　to　improve　the　heat　dissipation　of　electronic　devices,　reduce　the　problem　of　lower　devices　performance　and　short　working　life　which　was　caused　by　high　temperature,　the　friction　and　heat　transfer　characteristics　of　single　phase　forced　convection　in　developing　region　with　high　heat　flux　through　a　multiport　microchannel　flat　tube　(MMFT)　were　comparatively　investigated　by　experiments.　Furthermore　the　influence　of　heat　transfer　capability　in　MMFT　with　developing　flow　was　evaluated　by　three　aspects:　single/double-side　heating,　different　methods　of　eliminating　thermal　resistance　and　different　heat　flux.　The　hydraulic　diameter　of　the　tube　was　1.09　mm,　aspect　ratio　was　0.85　and　Reynolds　number　was　in　the　range　of　206~4　553.　The　results　indicate　that　friction　factor　obtained　by　experiment　is　in　good　agreement　with　the　classical　developing　channel　laminar　flow　theory.　In　addition　to　heat　transfer,　single-side　heating　is　superior　to　double-side　heating　whereas　the　discrepancy　reduces　with　the　increase　of　Reynold　number.　Different　thermal　resistance　has　obvious　effect　on　heat　transfer.　Brazing　lowers　the　surface　temperature　of　heating　device　10℃　than　thermally　conductive　silicone　grease.　When　Re＜1　000,　temperature　dependent　viscosity　variation　on　the　convective　heat　transfer　are　significant,　however　for　high　Reynold,　various　heat　flux　effects　Nusselt　number　little.　©　2017,　Editorial　Department　of　Journal　of　Beijing　University　of　Technology.　All　right　reserved.