Abstract: Based on the ITER water-cooling program, rotating test devices were built to investigate the compatibility of the fusion reactor materials RAFM steel, 316L(N) steel, and CuCrZr alloy with the Al₂O₃ water nanofluids in this study. The corrosion experiments were performed in nanofluids with different mass fractions of 0.01% and 1%,respectively. The observation and analysis on the specimen surfaces were performed by SEM, EDS, and XPS after corrosion experiments. It is shown that different mass fractions of nanofluids have slight effects on the corrosion performance of RAFM steel and 316L(N) steel and there are good compatibilities between RAFM steel, 316L(N) steel and nanofluids. The surface of CuCrZr alloy is covered by oxide film with holes and cracks. Furthermore, the surface morphology of CuCrZr alloy in nanofluids is strongly dependent on the testing duration, flowing velocity and mass fraction of nanofluids. The corrosion mechanism is dominated by oxygen absorption corrosion and mechanical erosion. The coupling effect of the two corrosions accelerates the corrosion process.