Lignin, as the largest renewable aromatic resource, has significant opportunities for producing high-value products via catalytic depolymerization. However, its complex structure and stable chemical bonds present challenges to its transformation. This study explores the catalytic depolymerization of lignin to aromatic monomers by means of Dawson-type phosphomolybdovanadate polyoxometalates (POMs), understanding the underlying mechanisms. Furthermore, vanadium modification is employed to adjust the catalyst's oxidative and acidic properties, demonstrating that the vanadium content in Dawson-type POMs greatly influences monomer yield. The highest yield is achieved with H