<p>All kinds of methods (physical, chemical and enzymatic) was used to enhance the functional properties of plant proteins. Soybean protein isolate (SPI) is a very important vegetable protein with higher nutritional values. The aim of the study was to evaluated the alternative application of hydroxyl-radical as a moderate‌ and homogeneous‌ protein handing technique to improve the functional qualities‌ of SPI. SPI was treated in H₂O₂ solutions at different concentrations (0, 0.1, 1, 5, 10 and 15 mM) for 24&#xa0;h and then freeze-dried. The oxidization induced more porous microstructure in SPI surface. Compared to the raw SPI, the total sulfhydryl group, water/oil holding capacity, enthalpy (peak 1 and peak 2), solubility of SPI with the increase of H₂O₂ concentration decreased significantly (<i>p</i> &lt; 0.05), which decreased by 40.03%, 7.30%, 39.46%, 12.07%, 16.71%, and 29.00% at 15 mM H₂O₂, respectively, while H₂O₂ prompted a significantly increase in protein carbonyl content (<i>p</i> &lt; 0.05). FTIR confirmed that oxidation resulted in the gradual loss of α-helical and β-sheet structures with the concomitant increase of β-turn and random coil structures (increased by 28.84% and 42.89% at 15 mM H₂O₂, respectively). Compared with the raw SPI, the moderate H₂O₂ concentration (1 mM) enhanced emulsifying properties, while lower (0.1 mM) and higher (5 mM) H₂O₂ concentration significantly increased the foaming properties and the value of zeta potential, respectively (<i>p</i> &lt; 0.05). With the increase of H₂O₂ concentration, the intensities of volatile compounds were strongly influenced by the oxidation levels of SPI, some compounds increased, some decreased, which was likely owing to the structure changes of modified SPI. These results indicated that the potential of H₂O₂ hydroxyl radical-generating system can be as an innovative‌ and productive‌ way to enhance functional properties of SPI, and also provide a key direction for developing high-performance plant protein ingredients in food industry.</p>