Overcoming the recalcitrance barrier of cellulosic biomass for efficient production of fermentable sugars at low cost is the current limitation for the industrialization of lignocellulosic biorefineries. In the present work, a two-step non-enzymatic strategy was developed for the fractionation of the main components in bamboo shoot shell (BSS) and conversion of polysaccharides into fermentable sugars by dilute acid in a γ-valerolactone (GVL)/H₂O solvent system. About 86.0% of lignin and 87.4% of hemicelluloses were removed in the first step by 0.6% H₂SO₄ under 140 °C for 1 h with the addition of 60% GVL. The residue solids enriched with cellulose were then subjected to acid hydrolysis employing 0.05% H₂SO₄ as the catalyst in 80% GVL at 180 °C for 20 min. The maximum total soluble sugar yield achieved in the acid hydrolysate was 70.7%. This research could provide valuable insights into the valorization of lignocellulosic biomass and become a promising alternative to the biomass-derived carbohydrate production scheme.