AbstractPretreatment of biomass is an extremely important step in a commercial biorefinery. For realization of lignocellulosic biomass as an alternative fuel source to occur, a fundamental understanding and critical investigation of the chosen pretreatment are essential. In this work, green liquor (GL) pretreatment of four plant species, namely Masson pine, poplar, moso bamboo, and miscanthus, was investigated to understand its effect on the chemical composition and enzymatic hydrolysis of different lignocellulosic materials. The results indicated that herbaceous materials exhibited better delignification selectivity in GL pretreatment than woody materials according to the order: miscanthus > moso bamboo > poplar > Masson pine. The effect of GL pretreatment on the enzymatic sugar yield was rather different depending on the varieties of lignocellulosic materials. Higher lignin removal with less polysaccharide degradation during GL pretreatment improved the enzymatic sugar yield.