A controlled experiment was conducted using Wisteria sinensis seedlings inoculated with Funneliformis mosseae to investigate the effects and physiological mechanisms of arbuscular mycorrhizal fungi (AMF) on the Pb stress tolerance of W. sinensis seedlings. Pb contamination gradients were established (400, 800, 1200 mg/kg) to measure the growth parameters (growth, biomass, tolerance index) and physiological indicators (chlorophyll content, malondialdehyde content, proline content and related antioxidant enzyme activities). AM fungi inoculation significantly enhanced both aerial and root growth of W. sinensis seedlings while improving the Pb stress tolerance. The translocation factor and shoot bio-concentration factor were lower than those of the control, whereas the root bio-concentration factor exceeded the level of the control groups. This demonstrated that AM fungi effectively reduced Pb accumulation in the aerial parts while significantly enhancing Pb sequestration capacity in the roots. Physiological analysis indicated that AM fungi-treated seedlings exhibited higher chlorophyll content and elevated the activities of antioxidant enzymes (SOD, POD, APX), along with significantly lower MDA accumulation compared to the non-inoculated controls. Principal component analysis combined with cluster heat-map visualization further demonstrated that AM fungi primarily enhanced the Pb tolerance of W. sinensis through three mechanisms: activation of antioxidant enzyme systems, regulation of growth-related processes, and modulation of chlorophyll biosynthesis pathways. The results provide theoretical and practical basis for mycorrhizal plant remediation of heavy metal pollution.