Abstract: To improve iron availability in the traditional Fe(Ⅱ)-activated persulfate (PS) process, degradation performance of trichloroethylene (TCE) in a Fe(Ⅲ)-(S,S)-ethylenediamine-N,N'-disuccinic acid (EDDS) activated PS system was studied, and the generation of reactive oxygen species (ROS) was investigated by means of radical scavenger tests. The effects of various factors, including initial PS concentration, Fe(Ⅲ)/EDDS molar ratio, solution pH and common anions in groundwater (Cl^-, HCO₃^-, SO₄^2- and NO₃^-) were evaluated. When the initial PS concentration was 15.0 mmol/L and Fe(Ⅲ)/EDDS molar ratio was 4,9.7% of TCE was removed in 60 min. TCE removal was found to be enhanced with increase of PS concentration and Fe(Ⅲ)/EDDS molar ratio, but did not further increase when either PS concentration or Fe(Ⅲ)/EDDS molar ratio was overdosed. In addition, elevating the initial solution pH value (from pH 3 to 11) led to decreases in TCE removal rate. Cl^-, HCO₃^-, SO₄^2- and NO₃^- adversely affected TCE degradation performance, and the extent of inhibition followed the sequence:HCO₃^->Cl^- >SO₄^2->NO₃^-. Radical scavenger tests showed that SO₄^-·, ·OH and O₂^-· were all responsible for TCE degradation in the PS-Fe(Ⅲ)-EDDS system, and ·OH was the dominant radical. In conclusion, the Fe(Ⅲ)-EDDS activated PS process was effective for TCE removal in aqueous solution, while ·OH played a critical role in the system. However, TCE degradation performance was affected by the solution matrix, which could be encountered in real contaminated groundwater.