An ion chromatography method was developed for determination of galacto-oligosaccharide in syrup.The components of syrup was eluted with water,250 mmol/L sodium hydroxide solution and 1mol/L sodium acetate solution in gradient,and using the CarboPac PA10(2 mm×250 mm) column and amperometric detector.The method presented linear correlation coefficient between 0.999 0 and 0.999 7,relative standard deviation(RSD) 1.54 % and 3.42 %.The recoveries of the lactose in syrup sample ranged from 91.7 % to 5.7 %.The method has many advantages,such as simple operation,fast determination,accurate and highly sensitive.