Abstract: Sample of compound fertilizer was treated as described in GB 15063-2001,and 10 mL aliquot of the filtrate were diluted 50 times to keep the mass concentration of Cl- at ca.20 mg·L-1.The Dionex Ionpac AS 23 column was used as stationary phase and the mixture of 0.8 mmol·L-1 NaHCO3 solution and 4.5 mmol·L-1 Na2CO3 solution was used as the mobile phase in the elution at the flow-rate of 1.0 mL·min-1.Suppression conductivity detection was used in measurements.Retention time was used for identification,and external standard method was used in determination.Linear relationship between values of peak area and mass concentration of Cl- ion was kept in the range of 5.0 to 50.0 mg·L-1.Recovery was tested by standard addition method,giving values of recovery in the range of 87.2% to 104.9%.Samples of compound fertilizer were analyzed by the present method and checked by the method of National standard,results obtained were found in good consistency.