Objective To study the influence of different critical plasma spray parameters (CPSP) on the microstructure and the wear property of nanostructured Al2O3-13% TiO2 coating deposited by plasma spraying so as to optimize the plasma spraying parameters. Methods Nanostructured alumina-titania coatings with NiCrAl as the transition layer and Al2O3-13% TiO2 as the ceramic layer on the surface of the Q235 steel were prepared by plasma spraying. The wear property of the coatings at room temperature and at high temperature was respectively tested, and phase constitutions and the microstructure of spraying powder and coating layer were respectively analyzed by XRD and SEM. Results The results showed that the nanostructured coating had a bio-model structure, consisting of PM region and FM region with defects such as crack and pore. The main phases were α-Al2 O3 , γ-Al2 O3 and rutileTiO2 . Lamination and spallation of coating materials, and the plastic deformation of nanostructured coating materials were the main reasons for coating system failure during the sliding wear test. Conclusion With the ascending of CPSP, the wear property increased, and the wear property at room temperature was better than that at high temperature. The presence of PM region and nanocrystals in the nanostructured Al2 O3 -13% TiO2 coating significantly increased the wear property.