Abstract: Ionitriding treatment at different temperatures(480, 500, 520, 540 ℃) was carried out on Y10 steel after quenching and tempering. The effects of nitriding temperature on the microstructure, hardness and high temperature friction and wear properties of the nitrided layer were studied. The results show that there was no white bright compound layer in the nitrided layer on surface of Y10 steel at different nitriding temperatures. The nitride in the nitrided layer was mainly composed of ε(Fe₃N) and γ′(Fe₄N). With the increase of nitriding temperature, the diffraction peak intensity of ε(Fe₃N) phase decreased, the diffraction peak intensity of γ′(Fe₄N) phase increased, the diffraction peak of α-Fe phase tended to disappear, and the thickness of nitrided layer increased. When the nitriding temperature increased from 480 ℃ to 540 ℃, the hardness of the nitrided layer increased from 880 HV to 999 HV, the stable friction coefficient decreased from 0.75 to 0.65, and the wear mass loss decreased from 0.74 mg to 0.34 mg. The high temperature wear resistance of the nitrided layer was improved with increasing nitriding temperature, which was mainly related to the formation of more high hardness nitrides in the nitrided layer.