To solve the deficiency of organic micro-pollutants removal in traditional technologies, the degradation study of chlortetracycline (CTC) in aqueous solution using UV activated persulfate technology (UV/PS combined process) was carried out. The removal effectiveness of CTC with UV process, PS process and UV/PS process was compared. Then the effects of initial CTC concentration, persulfate dose, as well as pH on the degradation rate of CTC were discussed. The active free radical in the reaction system was identified, and the reaction rate between the radical and CTC was determined. The results showed that CTC degradation with these three processes followed pseudo-first-order kinetic, and CTC removal efficiency can be significantly improved through the combination of UV process with PS process. The CTC degradation rate increased considerably as the persulfate dose increased, but decreased as the initial CTC concentration increased. The observed oxidation kinetic constant was influenced by pH values, and reached its highest and lowest level at pH 3 and 7 respectively．The active radical in the UV/PS process was SO₄^-·, and the reaction rate between CTC and SO₄^-·was 8.8×10⁸ L·mol^-1·s^-1.