Ten constituents have been isolated from the alcoholic extract of Astragalus membranaceus var. monghlicum root. All of them were identified. Among them astraisoflavanin (3S-(-)-mucronulatol-7-O-D-glucopyranoside) is a new compound. Dimethyl 4,4'-dimethoxy-5,6,5',6'-dimethylenedioxybiphyenyl 1-2, 2'-dicarboxylate is a known synthetic compound, but it was first isolated from natural resource Astragalus root and identified by the authors.