A proton-nuclear magnetic resonance(1H-NMR) method was established for the determination of polysaccharide content in mannatide using potassium acid phthalate as the internal standard.Effects of some experiment parameters were investigated.The optimal conditions were selected as follows:relaxation delay time(d1):1 s；transient number(ns):16.The results indicated that,under the optimal conditions,the good precision and repeatability for the method were obtained.The polysaccharide content in mannatide, determined by the 1H-NMR method with inner standard model,was similar to that of the ultraviolet spectrophotometry method.The established method was simple,specific and repeatable.Therefore,it could be used not only for the determination of polysaccharide content in mannatide,but also for detection of other kinds of polysaccharide with definite structures.