摘要： In the present study, Aluminum oxide (Al2O3) nanoparticles dispersed water based nanofluids were prepared via laser ablation in liquid method. Al2O3 nanoparticles were synthesized in deionized water using a nanosecond Nd-YAG pulsed laser operating at 1064 nm. The structural, optical and morphological characterizations of the produced nanofluids were performed. Thermal properties of the prepared samples were evaluated through thermal conductivity measurements which were carried out at various nanoparticles concentration and at temperatures ranging from 25 °C to 45 °C. Morphological analysis by transmission electron microscopy revealed spherically shaped Al2O3 nanoparticles with an average size of 9 nm. Moreover, the results indicated that the thermal conductivity of Al2O3-water nanofluid was improved as compared to the pure water. The increase in temperature and nanoparticles concentration leads to higher thermal conductivity of nanofluids. It was found that the thermal conductivity enhancement was around 8.6% at nanoparticles volume fraction of 0.7 vol.% and temperature of 45°C. This work proved the possibilities of fabricating Al2O3-water nanofluid with enhanced thermal conductivity via laser ablation in liquid medium without the use of hazardous chemicals and vacuum conditions. Therefore, the synthesized nanofluids have great potential to be applied in medium temperature applications.