This study addresses the concern of pesticide residues in vegetables by exploring the hydrogen peroxide assisted ultrasonic (H2O2/US) process for the removal of six pesticides from pakchoi, a popular green vegetable in China. Remarkably high efficiency was achieved, with removal rates reaching 83.9%, 68.8%, 85.9%, 91.6%, 75.6%, and 73.4% for dimethoate, dichlorvos, methiocarb, propoxur, chlorobenzuron, and etridiazole, respectively, through the H2O2/US process. A notable synergy was observed in the coupled H2O2/US process. The analysis of mass balance and degradation pathways indicates that the synergy stemmed from the efficient oxidation of pesticides by hydroxyl radicals (HO•) formed via sonolysis of H2O2. Surface properties of vegetables showed great impacts on pesticide removal by H2O2/US. Despite these treatments, the H2O2/US process exhibited minimal impact on vegetable quality. Overall, this study underscores the potential of the H2O2/US process as a promising technology for effectively removing pesticides from vegetables.