By the methylation method and GC MS analysis, we studied the distribution of carboxymethyl groups in the sugar backbone of CM AbPS and conclude that the carboxymethyl groups mainly substitute on 4 position of the fructofuranose of the sugar backbone. 并通过样品甲基化和GCMS分析,对羧甲基牛膝多糖糖链中羧甲基的分布进行了研究,结果表明羧甲基牛膝多糖中羧甲基主要取代在糖链中呋喃果糖的4位上。