An oxygen flask combustion-ion chromatography employed electrical conductivity detector for the determination of chloral hydrate in gliquidone main ring was developed.The organochlorines in gliquidone main ring was transformed to inorganic chlorines by oxygen flask combustion method,and eventually changed into chloride ion after absorbed by NaOH solution.Various ion chromatography conditions,e.g.mobile phase,flow rate and column temperature were investigated,and the optimal conditions were as follows:column:TSKgec SuperIC-Anion HS anion column;mobile phase: 7.5 mmol/L NaHCO3-1.1 mmol/L Na2CO3 solution;column temperature:40 ℃;flow rate:1.0 mL/min;detector:electrical conductivity detector.The results indicated that the method had a good specificity and precision(RSD≤2.0%).The calibration curve was linear over the chlorion concentration range of 0.025-0.080 mg/L with correlation coefficient of 0.999 9.The limit of detection(LOD)was 0.01 μg/L and the limit of quantitation was 0.05 μg/L.The spiked recoveries at 3 levels were in the range of 92.9%-103.4%with relative standard deviation of 6.4%.The method is convenient and effective for determinating the content of chloral hydrate in gliquidone main ring,and it could satisfy the requirement for qulity control of chloral hydrate as impurity in gliquidone main ring.