Abstract: The use of low-temperature plasma nitriding technology has become prevalent in metal heat treatment due to its high production efficiency, adaptability in processes, and eco-friendliness. In order to tackle the challenges posed by inadequate surface hardness and wear resistance in titanium alloys, this research utilizes a self-developed nitriding system that incorporates an IET arc ion source, focusing on low-temperature plasma nitriding of the TC4 titanium alloy （Ti-6Al-4V） with the goal of enhancing its properties. The experimental procedures were carried out at 500 °C, with a bias voltage of 400 V applied and a working pressure of 1.5 Pa maintained. Three distinct gas mixtures were employed （the volume ratios of nitrogen, hydrogen, and argon are 4∶0∶1, 4∶2∶1, and 2∶4∶1, respectively）, all of which were subjected to a consistent treatment period of two hours. Findings reveal that an appropriate addition of hydrogen can improve the diffusion capacity of nitrogen within the titanium alloy matrix, thus enhancing the nitriding effect and leading to the formation of dense TiN and Ti₂N layers. These changes notably increase the microhardness and wear resistance of the titanium alloy. Additionally, optimal wear resistance of the titanium alloy was observed at a nitrogen-hydrogen ratio of 2∶1. Consequently, the low-temperature arc nitriding technology proves capable of enhancing the surface properties of TC4 titanium alloy without modifications to the matrix structure and overall mechanical characteristics, therefore expanding the safe operating limits of TC4 titanium alloy. This also provides a viable process pathway and theoretical foundation for enhancing the surface performance of TC4 titanium alloy at low temperatures in applications such as aerospace and marine engineering, presenting a wider range of prospects for TC4 utilization.