In the present study, hydrodynamic (HD) cavitation was combined with sodium percarbonate (SP) for the pretreatment of lignocellulosic biomass. For HD cavitation, a circular flow system equipped with a venturi tube was employed. The combined system of HD and SP (HD-SP) was compared to a pretreatment system using ultrasonication and SP (US-SP). The efficacy of each pretreatment method was evaluated by measuring lignin removal, and glucose and xylose formation. Fourier transform infrared spectra indicated that both systems resulted in a similar degree of lignin removal; however, the HD-SP system was more efficient than the US-SP system for glucose and xylose production. Neither system generated the inhibitor furfural, while it was detected in dilute acid (DA)-pretreated biomass. Furthermore, changing the venturi tube throat diameter improved the efficacy of the HD-SP system. The HD-SP system is promising for the industrial pretreatment of lignocellulosic biomass.