SiO2,　Al2O3　and　TiO2　nanofluids　based　on　deionized　water　with　a　particle　volume　fraction　of　0.1%　were　prepared　by　the　two-step　dispersion　method.　Surfactants　were　added　into　the　nanofluids　to　reduce　particle　aggregation　and　enhance　stability.　An　ultraviolet　spectrophotometer　was　used　to　test　the　absorbance　of　nanofluids　as　the　absorbance　decreased　with　decreasing　concentration　of　nanoparticles　suspended　in　liquid.　Based　on　the　principle　of　transient　plane　source　(TPS)　method,　the　2500S　thermal　constant　analyzer　was　employed　to　conduct　the　thermal　conductivity　of　nanofluids.　In　order　to　investigate　the　heat　transfer　performance　in　a　triangular　microchannel　heat　sink　using　nanofluids,　an　Infrared　Thermal　Camera　(ImageIR　3350,　Germany)　was　inverted　and　hanged　immediately　over　the　microchannel　heat　sink　to　observe　the　temperature　distribution　on　the　substrate.　The　condition　of　heat　dissipation　was　imitated　by　a　DC　power　supply　(34420A,　Agilent,　China),　which　would　energize　to　the　thin　film　heater　at　a　heat　flux　of　q=200　Wcm-2.　As　different　nanofluids　were　studied,　DI-water　was　used　to　clean　the　experimental　system　after　the　previous　experiment　was　done　to　avoid　the　residues　of　nanoparticles.　The　results　reflected　that　the　surfactants　had　effect　on　the　absorbance　of　nanofluids,　and　the　particles　would　aggregate　with　the　increase　of　standing　time.　The　thermal　conductivity　and　convective　heat　transfer　were　improved　by　adding　nanoparticles.　The　average　temperature　on　substrate　was　cooled　down,　and　the　uniformity　of　temperature　was　also　repaired.　As　the　result,　TiO2　nanofluids　had　a　better　behavior　than　SiO2　and　Al2O3　nanofluids.　©　All　Right　Reserved.