Polysaccharide-based aerogels combine high porosity, low density, excellent biocompatibility, and tunable functionality, making them attractive for a wide range of applications. In this study, xanthan gum (XG) was used to fabricate nanoporous aerogels with finely structured nanofibers via metal-ion crosslinking, followed by solvent exchange and supercritical CO2 drying. The resulting XG aerogels exhibit a high specific surface area (391 m2·g-1), ultra-high porosity (98.7%), and low density (0.059 g·cm-3), achieving an ultra-low thermal conductivity of 17.0 mW·m-1·K-1. The robust crosslinked network also provides excellent mechanical performance, with a compressive modulus of 2.75 MPa. Hydrophobic treatment enables it to adapt to a wider range of environmental conditions. These features make XG aerogels promising high-performance thermal insulation materials for applications in energy conservation and environmental protection.