Depolymerization of technical lignin to platform aromatic monomers can significantly increase the productivity and profitability of biorefinery. Establishing an efficient and economical way for technical lignin depolymerization is vital to make this process practical. Herein, we report the one-pot depolymerization of technical lignin into aromatic monomers without added catalyst and external H2 gas. Ethanol, as an inexpensive and recyclable solvent, was used to induce the technical lignin hydrogenolysis. The significant solubility and H-transfer ability of ethanol resulted in an exceptional hydrogenolysis efficiency of the β-O-4 lignin linkages, giving an aromatic monomer yield of 20.62C% at 300 °C for 4 h, rival those from technical lignin disassembly with metal catalysts and added H2 gas. Over 14.70C% of the monomers could be identified, among which phenol, guaiacol, 4-ethyl phenol, 4-ethyl guaiacol, and syringol were obtained with prominent yields. The depolymerization procedure was thoroughly recognized with GC × GC–MS, GPC, MALDI-TOF-MS, HSQC NMR, and FT-ICR-MS analyses to provide an in-depth understanding of the molecular weight, functionality, and elemental composition evolutions of the technical lignin.