The mass application of lignin is challenging due to poor processability and low reactivity. The processes to refine lignin into fine chemicals always tedious and produce multi-components chemicals, which cannot be utilized directly. In this work, hot-compressed ethanol/H2O has been adopted to treat lignin to realize its atomic economy utilization. The single O-methoxyphenol chemical has been obtained by convenient organic phase extraction, and the partial depolymerization products contain in aqueous phase. The partial depolymerization products have been applied for preparation of epoxy resin com-posite. The mechanical properties of the epoxy resin/lignin composites are considerably improved due to the chemical interaction between the activated depolymerized lignin and epoxy. Additionally, an aminofunctionalized depolymerization was inspected by introducing amine into the ethanol/H2O medium, by which the curing agent usage can be partially reduced. This study provides an efficient strategy for lignin utilization to obtain O-methoxyphenol and high-performance polymer composite. (c) 2020 Published by Elsevier Ltd.