To enhance heat exchange under high temperature condition，a nanofluid with alumina nano-particles suspended in propylene glycol and water（base liquid）was prepared.The boiling point，thermal conductivity，specific heat and viscosity were measured respectively by ebulliometer，transient hot-wire method，comparison method and rotation viscometer.The heat exchange coefficient and flow resistance of 1%—5%（vol）nanofluids were measured in the plate-pin oil cooler test.The experimental results showed that nanoparticles could significantly enhance the heat transfer capability of base liquid.Particle volume fraction and fluid temperature had important effect on thermal properties of nanofluids.The boiling point of nanofluids was over 120℃，a little lower than that of base liquid.Adding particle volume fraction would decrease specific heat but increase thermal conductivity，viscosity and heat exchange coefficient.In Test 2，the mean heat exchange coefficient of 5%（vol） nanofluid in the plate-pin oil cooler was 124.56％ higher than that of base liquid，while the flow resistance rose moderately.