Abstract: Metal fuel is a major candidate fuel type for the next generation nuclear energy systems such as fast neutron reactors. However, the irradiation swelling problem caused by gaseous fission products is quite significant, which can easily lead to cladding rupture at a relatively shallow fuel burnup, thus limiting its application performance. Xenon is one of the inert gases generated in reactor core, so it is important to study the behavior of xenon in metal fuel. In this paper, the diffusion behavior of xenon in uranium-zirconium alloy fuel was systematically studied using molecular dynamics method. The diffusion characteristics were analyzed, and the corresponding diffusion coefficients at different temperatures and zirconium contents were calculated. Furthermore, a fitted quantitative function relationship between the diffusion coefficient of xenon and temperature as well as zirconium content was established. The results show that the diffusion coefficient of xenon increases with the increasing temperature in uranium-zirconium alloy, which is in agreement with the Arrhenius equation. When the zirconium content is 10%, as the temperature rises from 1 050 K to 1 400 K, the diffusion coefficient of xenon increases from 0.007 8×10⁻⁸ m²/s to 0.120 6×10⁻⁸ m²/s with the corresponding diffusion activation energy of 1.04 eV. The xenon diffusion can be hindered by the addition of zirconium in an appropriate amount, thereby improving the irradiation resistance of metal fuel. When the zirconium content increases from 0 to 50%, the diffusion coefficient of xenon decreases from 0.071 3×10⁻⁸ m²/s to 0.015 3×10⁻⁸ m²/s. However, when the zirconium content exceeds 50%, as the further addition of zirconium, the alloy composition gradually transforms into pure zirconium, which promotes the diffusion of xenon instead. Additionally, xenon tends to aggregate and form clusters in uranium-zirconium alloys. The cluster size increases with the increasing temperature, and initially decreases and then increases with zirconium content, reaching the minimum value at a zirconium content of 60%. The cluster evolution trend is generally consistent with the relationship of the diffusion coefficient with temperature and composition. As a result, the formation of xenon cluster is closely related to its diffusion behavior, and the enhancement of xenon diffusion is beneficial to the formation of large-sized clusters. The fitted function relationship between the diffusion coefficient of xenon, temperature, and zirconium content contains a certain physical implication, i.e., the first item represents the initial diffusion coefficient, and the second item represents diffusion activation energy. The study results can provide theoretical support for the design and performance optimization of metal fuel.