Lignin, a renewable and biodegradable polymer, offers a promising alternative to petroleum-based polyols for polyurethane elastomer synthesis. However, its complex structure poses challenges, such as poor dispersibility and reactivity. This study introduces a novel one-step and solvent-free method for synthesizing lignin-containing polyurethane elastomers (SF-LPUes-ONE) with a high lignin substitution rate of at least 30 wt%. By directly incorporating a dispersion of ethanol-extracted lignin and long-chain polyols into the reaction with isocyanates, we successfully prepared SF-LPUes-ONE with remarkable mechanical properties. The tensile strength, elongation at break, and toughness of the resulting sample reached 42.3 MPa, 584.7 %, and 110.0 MJ/m