An electrooxidation strategy mediated by reactive oxygen species is proposed to realize the transformation of styrene to benzaldehyde on a Pt anode, with a high selectivity of ca. 89% and faradaic efficiency of 28.8%. Isotopic labelling, electron paramagnetic resonance and radical scavenging experiments revealed that OH˙ and O 2 - ˙ species, formed in situ via anodic water oxidation, play a crucial role in the selective formation of benzaldehyde.