Abstract: In this report, the decomposition kinetics of thalidasine (TD) in aqueous solution at pH 2.0～7.8, salt concentration 0～0.132mol/L, temperature 50, 60, 70,80℃, and different oxygen concentrations were investigated. The decomposition rate constant of TD in aqueous solution were determined by fluorescence spectrophotometer.The results showed: the oxidation reaction contributed largely to the overall decomposition, the oxidation rate of TD was found to be chiefly dependent on the pH of the medium and presence of oxygen. When in excess oxygen, the reaction followed pseudo firstorder kinetics with respect to TD concentration. The rate constant can. be expressed as:■ No primary salt effect was observed at pH 7.2.