Abstract: Chlortetracycline is a kind of broad-spectrum antibiotics which is used for treating human diseases and animal diseases,and as a kind of persistent organic pollutants(POPs) remained in the aquatic environment.The degradation of CTC with the influence of Fe³⁺ was discussed via complexation reaction mechanism and under different conditions(ratio of n(Fe³⁺) to n(CTC),temperature and pH).Resultsshow that the CTC-Fe³⁺ complex is likely formed with the A-ring and that a single unit of CTC can complex with a maximum of two units of Fe³⁺.The degradation rates are different with different concentrations of Fe³⁺.When the ratio of n(Fe³⁺) to n(CTC) reaches 1∶1,the degradation rate attains the maximum value.In the presence of Fe(Ⅲ) with the same concentration to CTC,the degradation rate of CTC is significantly enhanced 271% and 322% at 10 ℃ and 20 ℃,respectively(however,the effect of Fe³⁺ was not significant at 30 ℃),and by 400%,141% and 179% at pH 3,5 and 7,respectively.Because of the abundant appearance of Fe³⁺,the results can provide a scientific basis for the determination of actual engineering environment condition and the modeling of CTC's degradation in pharmaceutical wastewater treatment.