Abstract: Ion chromatography with suppression conductometric detection was applied to the determination of anions and cations in sea water.The use of suppression-conductometry showed the special features of lowering the background of the eluent,increasing the conductance of the detected ions and improving the S/N ratio.Amounts of H+ and OH- required to suppress the eluent were supplied by an electrochemical self-generating suppressor through continuous electrolysis of water.Anions and cations in sea water were separated and determined simultaneausly by the combining use of anion separation column (and/or cation separation column) with suppression-conductometric detection,and by the use of equi-grading and/or gradient elution.Data of linear regression equations and detection limits of 7 anions and 6 cations were given.