Nanofluid　is　one　of　the　most　popular　and　promising　heat-transfer　fluids.　SiO2/water　nanofluid　suspension　stability　and　their　thermophysical　characteristics　were　investigated.　Specifically,　the　suspension　stability　of　the　nanofluid　was　characterized　using　a　Malvern　Zetasizer　Nano　Instrument.　The　thermal　conductivity　of　the　nanofluid　was　studied　at　different　temperatures　and　particle　sizes.　The　results　indicated　that　the　thermal　conductivity　of　the　nanofluid　with　a　mass　fraction　of　5%　increased　to　6.8%　compared　with　the　water　based　fluid.　Meanwhile,　the　mean　field　synergy　angle　of　the　spiral　microchannel　radiator　with　different　properties　of　the　nanofluid　was　simulated　based　on　different　structure　microchannel　sizes　to　evaluate　the　heat　transfer　performance　according　to　the　velocity　and　the　temperature　field.　The　results　indicated　that　the　mean　field　synergy　angle　was　proportional　to　the　nanoparticle　size　while　inversely　to　the　mass　fraction　of　the　nanofluid,　and　their　strengthening　heat　transfer　effect　was　enhanced.　The　structure　size　of　the　microchannel　was　one　of　the　important　effect　factors　on　the　mean　field　synergy　angle.　Published　by　AIP　Publishing.