Objective To explore the moisture absorption and related components of aqueous extract of Salviae Miltiorrhizae Radix et Rhizoma. Methods The hygroscopicity of aqueous extract of Salviae Miltiorrhizae Radix et Rhizoma and its water and alcohol elution parts separated by macroporous resin was measured, and the contained low molecular sugars (monosaccharides, oligosaccharide), polysaccharide, protein, amino acid, tannins and salvianolic acid B, etc. were analyzed. Results D101 macroporous resin was used for separation and purification of aqueous extract of Salviae Miltiorrhizae Radix et Rhizoma. The hygroscopicity of water elution parts was enhanced;carbohydrate, protein and other hydrophilic substances content increased; the content of salvianolic acid B was reduced to 1.76 mg/g. While the hygroscopicity and hydrophilic substances of alcohol elution parts were greatly reduced; the content of salvianolic acid B increased to 146.57 mg/g. Conclusion The hygroscopicity of aqueous extract of Salviae Miltiorrhizae Radix et Rhizomais closely related to the contained strong hydrophilic components, such as low molecular sugars, etc. Using D101 macroporous resin to purify aqueous extract of Salviae Miltiorrhizae Radix et Rhizoma can not only effectively gather the contain phenolic acids active ingredients, but also sharply decrease the extract yield and extract moisture absorption.