Objective To establish a method for simultaneous determination of dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) in drinking water by carbonate system ion chromatography. Methods The water samples were pretreated with 0.22 μm aqueous microporous filtration membrane.The separation was carried out on an AS23 anion analyzer column with 4.0 mmol/L sodium carbonate solution as eluent and isogradient elution.Using a conductivity detector for detection. Results The linear equations of DCAA and TCAA were y=1.495x+0.001 (r=0.998) and y=1.112x-0.007 (r=0.998),respectively.The relative standard deviations (RSD) were 0.57%-7.17%.The recovery rates were 98.7%-99.6%.The detection limits were 0.000 20 mg/L and 0.000 50 mg/L,and the quantification limits were 0.000 80 mg/L and 0.002 0 mg/L,respectively. Conclusion The method is easy to operate and the sample pre-treatment is simple.It is suitable for the detection of DCAA and TCAA in drinking water.