An ion chromatographic(IC) method was developed for the determination of trace anions in high purity sodium hydroxide after sample neutralization and column concentration.Samples were dissolved and diluted with de-ionized water,and then injected into the IC system directly without any further pretreatment．The sample solution was delivered with de-ionized water,firstly on-line filtrated with In Guard H column for pre removing OH-,and then concentrated with IonPac TAC ULP column.The anions under test in the enrichment column were delivered in the IC system when the valve was switched．With the eluent KOH produced by eluent generator at a flow rate of 1.0 mL/min,the anions were separated on an IonPac AS11-HC column and detected with conductivity detector,then quantitively analyzed by the external standard method．The results indicated that the correlation coefficients of chloride,sulfate,chlorate were 0.999 8,0.999 6 and 0.999 2,respectively,in the linear range of 0.1-10.0 mg/L.The detection limits for chloride,sulfate,chlorate were 0.03,0.07,0.06 mg/kg,respectively,and their spiked recoveries were 92%-104%,91%-111% and 92%-106%,respectively,with their relative standard deviations (n=7) not less than 2.0%.The method was applied in the determination of anions in high purity sodium hydroxide samples with satisfactory results.