In order to remove the typical refractory pollutant carbamazepine (CBZ) in water, a vacuum ultraviolet/chlorine advanced oxidation system was constructed, and the difference of CBZ removal efficiency in different oxidation systems based on vacuum ultraviolet or free chlorine was investigated; The effects of pH value, free chlorine dosage, bicarbonate in water, and humic acid on the removal of CBZ by vacuum ultraviolet/chlorine system and the attenuation of free chlorine in the system were explored. Through the free radical quenching test, the main active substances that oxidize CBZ in the vacuum ultraviolet/chlorine system were further explored. The results show that when pH=6, the chlorine dosage is 8 mg/L, the initial CBZ concentration is 30 μmol/L, the CBZ removal rate exceed 99.5% after 16 minutes of reaction in the vacuum ultraviolet/chlorine system; under the same conditions, the rate constant of the vacuum ultraviolet/chlorine system to remove CBZ is 1.75 and 5.30 times that of vacuum ultraviolet system and UV/chlorine system. Vacuum ultraviolet and free chlorine have a synergistic effect on removing CBZ.Under acidic conditions, the removal effect of CBZ is better, and the optimal reaction pH value is 6; the dosage of free chlorine is an important factor affecting the degradation rate of CBZ, and the best dosage of free chlorine is 8 mg/L; while bicarbonate and natural organic matter in the water both have an inhibitory effect on the removal of CBZ; during the degradation of CBZ by the vacuum ultraviolet/chlorine system, the main free chlorine consumption is ultraviolet light excites and consumes and reacts weakly with CBZ and degradation products, the system has oxidation of HO· and Cl· and direct photolysis.