通过凝胶层析法对土壤腐植酸进行了分组提取，并对其各分子量分级组成及其与Ｃｄ、Ｚｎ的络合特性进行了研究。结果表明：土壤胡敏酸通过Ｇ５０可以分成３个较集中的组分，分子量分别为Ｍ＝７８１８０、Ｍ＝４８３３９及Ｍ＝２２８６３；通过Ｇ１００可以得到２个组分，分子量分别为Ｍ＝６３３４３和Ｍ＝１９８７０。富里酸通过Ｇ５０、Ｇ１００层析，则从总体上成为单一的宽带，分子量约为Ｍ＝２３００。腐植酸对Ｃｄ、Ｚｎ络合量的测定显示：胡敏酸对Ｃｄ、Ｚｎ的络合量呈２个明显的峰值，而富里酸只有１个峰值。两者对Ｃｄ、Ｚｎ络合量随洗脱体积的变化曲线与其吸光值随洗脱体积的变化曲线相一致。６５Ｚｎ示踪技术研究６５Ｚｎ与胡敏酸、富里酸络合的结论与常规方法一致。 The soil humic acid was extracted by gel chromatography, and its molecular weight fractionation and its complexation with Cd and Zn were studied. The results showed that the soil humic acid could be divided into three concentrated components by G50, the molecular weights were M = 78180, M = 48339 and M = 22863, respectively. Two components were obtained by G100, the molecular weights were M = 63343 and M = 19870. Fulvic acid through G  50, G  100 chromatography, the overall become a single broadband, molecular weight of about M = 2300. The determination of the complexation amount of Cd and Zn by humic acid showed that there were two obvious peaks for the complexes of humic acid to Cd and Zn, while the fulvic acid had only one peak. The curves of the amount of Cd and Zn complexing with elution volume are consistent with the changes of their absorbance values ​​with the elution volume. 65Zn tracer technology 65Zn and humic acid, fulvic acid complex with the conventional method of conclusion.