The treatment of phenol wastewater with an ultraviolet source and an oxone generator by introducing salicylic acid as the capturer is described. The presence of HO·during the phenol degradation has been proved. The impacts of factors such as acidity and reaction time on the HO· formation are also discussed. The results demonstrate that HO· generated from ozone/UV oxidation under a basic condition is the immediate cause of phenol degradation. At room temperature and a pH value of 9.93, the degradation of phenol occurs rapidly within 0.5 min and the removal of phenol(100 mg/L) is above 98.5% within 15 min; in the meantime, the pH value declines gradually with the degradation of phenol. A discussion about the formation and the transformation of the intermediate products during phenol degradation is included.