Abstract: Ion-chromatography was appled to the determination of radiation waste water sample of radiation waste water was diluted 1 250 times and 100 μL of the diluted sample solution was introduced into the instrument for IC determination.Calibration curve was prepared by adding standard sulfate solutions of different concentrations to the matrix solution prepared from waste water sample after removal of the sulfate by precipitation with barium ion.By applying the high multiple dilution as described above,not only the radiation of the water sample was reduced to a great extent,but also the interference of precipitation of co-existing metal ions possible to clog the chromatographic column was eliminated.Correlation coefficients of 0.998 6 (sample matrix 1) and 0.997 4 (sample matrix 2) were obtained showing satisfactory linearity of the calibration curves.Detection limit of the method was found to be 18.9 μg·L-1.Precision was tested and the value of RSD (n=8) obtained by measuring the peak area was 1.46%.Recovery was also tested,giving values in the range from 96.7% to 103.8%.