This study set up a new method to conduct the simultaneous determination of uronic acid, amino sugar and neutral sugar in the polysaccharide from Angelica sinensis using pre-column derivatization. In this paper, D-mannose, D-glucosamine, L-rhamnose, D-galactosamine, D-glucuronic acid, D-galacturonic acid, D-glucose, D-galactose, L-arabinose and L-fucose were made into pre-column derivatives to serve as the standard for acidic Angelica polysaccharides (AAPS) analysis. Samples were separated on a Hypersil BDS C18 column (4.6 mm×250 mm, i.d.) and detected by UV detection at 250 nm wavelength. The mobile phase was composed of ammonium acetate buffer (100 mM, pH= 5.0), acetonitrile and tetrahydrofuran in the ratio of 81﹕17﹕2. Experiments were performed at 25 °C with a flow rate of 1.0 ml/min. Our study found that AAPS is composed of D-mannose, D-glucosamine, L-rhamnose, D-galactosamine, D-glucuronic acid, D-galacturonic acid and D-glucose in a molar ratio of 1.7﹕13.9﹕1.3﹕1.3﹕2.3﹕2.1﹕1.