Abstract: This work aimed to evaluate the impact of oat β-glucan addition (1%, 2%, 3%, 4%, and 5%) on the hydration behavior and technological characteristics of waxy rice flour, with the goal of providing a scientific foundation for enhancing the quality and functional properties of waxy rice flour-based products. The results demonstrated that as the β-glucan addition level increasing, the average particle size of rice flour-β-glucan composite decreased from 58.86 μm to 53.17 μm. Nevertheless, the repose and sliding angle of the composite significantly increased (P<0.05), which implied reduced flowability. The water absorption capacity and solubility increased from 14.3% and 7.63% to 16.6% and 15.38%, respectively. In contrast, the swelling power slightly decreased, and the contact angle was reduced, suggesting enhanced hydrophilicity and significantly improved hydration capacity of the composite system. Meanwhile, the onset temperature of waxy rice flour increased from 70.7 ℃ to 73.8 ℃, and the peak viscosity decreased from 695.6 mPa·s to 433.6 mPa·s, indicating an enhancement in its thermal stability. In addition, the addition of β-glucan led to a reduction in the consistency coefficient and storage modulus of the composite gel, while the flow behavior index increased, suggesting weakened elasticity and structural stability of gel network. In conclusion, oat β-glucan can enhance the hydration capacity of waxy rice flour and thereby improve its processing properties, thus promoting its development and application in the field of functional foods.