Abstract: A nitrogen plasma flame produced by a modified TIG welding torch was applied to heat the pure titanium specimens in the atmosphere directly and make them nitrided with the N₂+Ar plasma gas mixture, so that the nitrided layer was obtained through the interaction between Ti element of the substrate surface and N element of the plasma flame. The changes of the microstructures and properties of the nitrided layers were mainly studied by changinvg the nitriding temperature and nitriding time. And the better nitriding processing parameters were obtained. The mechanism of the nitrided layers and their morphologies both surface and cross-section were investigated by optical microscopy, scanning electronic microscopy, X-ray diffraction and so forth. The surface micro-hardness and the wear resistance of the nitrided layers were tested as well. The experiment and analysis results showed that the nitrided layers were mainly composed of TiN phase. The homogeneous and dense nitrided layers were well metallurgically combined with the substrate. And also they can effectively improve the wear resistance of the pure titanium substrate.