The core concept of this technology is to convert lignin into a renewable feedstock capable of partially replacing petroleum-derived raw materials. Lignin is a natural aromatic constituent of plant cell walls and can be obtained from agricultural and forestry residues, pulp and paper by-products, and wood-processing residues. Conventional phenol-formaldehyde resins are primarily synthesized using petroleum-derived phenol as the main raw material. In contrast, this technology employs a liquefaction process to overcome the poor solubility and limited processability of lignin, enabling it to react with formaldehyde for the preparation of lignin-based phenol-formaldehyde resins. Plywood prepared using these lignin-based resins showed, in selected formulations, bonding strength comparable to that of conventional phenol-formaldehyde resins. In addition, the free formaldehyde emission of the resulting materials can meet the F1 grade requirements of national standards for low-formaldehyde building materials. The key advantages of this technology include enhancing the utilization value of lignin, reducing partial reliance on petroleum-derived phenol, lowering process energy consumption, and increasing the bio-based content of the resin system. This technology can also be extended to impregnated laminates, furniture panels, and building boards.