A novel complex oxide of Cu-Bi-V-O was hydrothermally synthesized in a Bi2O3-V2O5-CuO-H2O system, and it was found that this compound is catalytically active for phenol hydroxylation by H2O2, which is comparable to TS-1. Reaction temperature, solvent, the molar ratio of phenol to H2O2, reaction time, catalyst amount, and method of H2O2 addition were found to be major factors for phenol conversion and product selectivity. Furthermore, electron spin resonance (ESR) was used to characterize the reaction intermediates, two species assigned to hydroxyl radicals and hydroperoxyl radicals were observed, and the hydroxyl radicals are proposed to play important roles in the formation of products in catalytic phenol hydroxylation by H2O2.