Corn bran is a major by-product of corn starch processing. Due to its high cellulose and hemicellulose contents and relatively low lignin abundance, it represents a promising feedstock for biorefineries. However, efficiently deconstructing corn bran cell wall to maximize fermentable sugar yield while minimizing inhibitor formation remains a challenge due to the complex cross-linked structure of its lignocellulosic matrix that hinders substrate accessibility and prone to side reactions during deconstruction. This study systematically evaluated various pretreatment strategies and identified dilute sulfuric acid as the optimal method to maximize hemicellulose dissolution and total sugar recovery while maintaining low levels of refractory phenolic inhibitors (1.03 g/L, far lower than alkaline and sulfite-based pretreatment). Under optimal conditions (0.80% v/v sulfuric acid, 129 °C, and 23 min), the hemicellulose dissolution rate reached 99.58%, with a pentose yield of 0.38 g/g corn bran and hexose yield of 0.16 g/g corn bran. Subsequent enzymatic hydrolysis of the solid residue (20 FPU/g initial dry weight cellulase) further released hexose-rich sugars. The integrated process achieved a significant total reducing sugar yield of 0.79 g/g corn bran. These findings demonstrate an effective pathway for the high-value utilization of corn bran and provide a scalable process strategy applicable to other lignocellulosic agricultural wastes for sustainable bioenergy production.