A　modified　Buongiorno　model　of　nanofluids　was　established　with　full　considerations　of　scaling　effects　and　four　driving　mechanisms　of　nanoparticles　migration　in　micro-channels.　In　order　to　reveal　nanoparticles　migration,　heat　transfer　and　pressure　drop　characteristics　of　alumina-water　nanofluid　in　hydrodynamically　and　thermally　fully　developed　region　of　micro-channels,　the　proposed　governing　equations　were　solved　by　means　of　the　Runge-Kutta-Gill　method.　The　obtained　results　demonstrated　that　the　viscous　dissipation　term　exhibits　adverse　influence　on　heat　transfer　performance　for　heating　and　cooling　cases.　Moreover,　it　has　been　found　that　the　increase　of　the　amount　of　slip　velocity　and　temperature　jump　at　the　wall　not　only　enhances　heat　transfer,　but　also　decreases　pressure　drop,　indicating　promising　application　prospects　of　nanofluids　in　micro-channels.　Eventually,　four　driving　mechanisms　of　nanoparticles　migration　are　discussed.　The　results　clearly　indicated　that　Brownian　diffusion　and　thermophoresis　are　more　important　than　shear-induced　diffusion　and　viscosity　gradient-induced　diffusion.　©　2016　Elsevier　Ltd.