The degradation and its kinetics of chlorine chlorination of phenol in disinfection process was studied. The influencing factors were investigated, such as chlorine dosage, temperature and background organic compound and so on. The experimental results showed that the degradation of phenol by chlorine followed second-order kinetics. The temperature influenced the reaction sharply, and it followed Van't Hoff Rule. The removal efficiency of phenol would increase with higher temperature. Under different background UV254 (humic acid), the degradation rate of phenol would slightly decrease. With increasing concentration of ammonia-nitrogen, the degradation rate of phenol would slower.