Abstract We measured the critical heat flux (CHF) and boiling heat transfer coefficient (BHTC) of water-based Al2O3 (alumina) nanofluids. To elucidate the stabilizer effect on CHF and BHTC of alumina/water nanofluids, a polyvinyl alcohol (PVA) was used as a stabilizer. The plate copper heater (10×10mm2) is used as the boiling surface and the concentration of alumina nanoparticle varies 0–0.1vol.%. The results show that the BHTC of the nanofluids becomes lower than that of the base fluid as the concentration of nanoparticles increases while CHF of it becomes higher. It is found that the increase of CHF is directly proportional to the effective boiling surface area and the reduction of BHTC is mainly attributed to the blocking of the active nucleation cavity and the increase of the conduction resistance by the nanoparticle deposition on the boiling surface.