Abstract: The protective effect of coatings isolates metal materials from corrosive media and forms a long-term physical barrier, playing a crucial role in metal corrosion protection. Dendritic mesoporous silica nanoparticles (DMSNs) are widely used as efficient functionalized carriers/reaction platforms due to their three-dimensional central radial pore structure, large specific surface area, and large pore volume. Functionalized DMSNs-modified lignin-based polyurethane corrosion-resistant coatings were designed and prepared, and their corrosion protection performance in standard salt solution corrosion environments was systematically studied. Electrochemical impedance spectroscopy results showed that after 15 d of immersion, the low-frequency impedance modulus of the functionalized DMSNs-doped lignin-based polyurethane corrosion-resistant coating remained as high as 1.15×10⁸ (Ω·cm²), indicating its excellent shielding effect and corrosion-resistant performance. This provides new insights into the application of functionalized DMSNs in efficient polyurethane corrosion-resistant coatings.