Refined lignin is prepared from industrial alkali lignin obtained from papermaking black liquor, the influence of NaOH solution concentration and H2SO4 concentration on the extraction rate of refined lignin is explored, and the foam density and compressive strength of refined lignin-based polyurethane foam materials are explored. Tensile strength improves the extraction rate of refined lignin, refined lignin improves the mechanical properties of polyurethane foam materials, enhances the utilization rate of lignin, reduces the production cost of polyurethane foam materials, and expands the scope of use. Refined lignin is obtained through alkali-dissolving acid precipitation, liquid-liquid extraction and ultrafiltration membrane filtration treatment process, and the refined lignin-based polyurethane foam material is synthesized by the prepolymer method. When the concentration of NaOH solution is 2.5 mol/L, the extraction rate is the highest; the concentration of H2SO4 has no obvious effect on the extraction rate; the addition of refined lignin increases the foam density and improves the compressive and tensile strength. When the mass fraction of refined lignin is 10%, the mass of dibutyltin dilaurate is 0.24 g, and the mass of triethanolamine is 0.04 g, the performance of the refined lignin-based polyurethane foam material is optimal.