In this study, a novel polysaccharide (PSH) with potent anti-gout activity was extracted and separated from Sanghuangporus vaninii (S. vaninii). The structural characteristics of PSH were elucidated using analytical techniques. HPLC analysis revealed that PSH was a heteropolysaccharide with a molecular weight of 5.25 × 10⁴ Da. FT-IR, NMR, and GC-MS collectively demonstrated that PSH was a pyranose with both α and β configurations, primarily composed of Glcp-(1→, →4)-Glcp-(2→, →3)-Galp-(1→, and Araf-(1→ linkages. The cell viability confirmed the non-toxicity of PSH. CAT and SOD showed that compared with the model group, PSH significantly offset the oxidative damage induced by MSU (p < 0.01). The results from ROS and MDA mutually corroborated the antioxidant capacity of PSH. Furthermore, PSH effectively suppressed MSU-triggered inflammatory responses. The antioxidant and anti-inflammatory experiments provided evidence for the anti-gout efficacy of PSH. Collectively, these findings support the potential development of PSH as an anti-gout active substance.