A high performance ion exchange chromatographic method coupled with pulsed amperometric detection was established for the analysis of amylopectin chain length distribution.The amylopectin was hydrolysised into unit chain under the function of isoamylase which can broke the α-1，6 chain of glucan.The determination method was optimized by comparing different chromatographic columns and elution conditions.Water,100 mmol/L NaOH and 1 mol/L NaAc+100 mmol/L NaOH aqueous solution were used as mobile phase,and the analysis of degree of polymerization (DP) more than 80 could be achieved by using CarboPac PA20 anion exchange column.Maize,cassava,potato and rice starch were selected as the example for the determination of chain length distribution,which could be used to judge their molecular configurations.This method was proved to be simple,extensive and reproducible,and the RSD was less than 5% when the DP was under 65.The method could provide the basis for further research of physical and chemical properties of starch and breed improvement.