Objective: To study the chemical constituents of ethanol extract of Astragalus membranaceus var. mongholicus. Method: The chemical constituents were isolated and purified by various chromatographic techniques and the structures were determined by physico-chemical properties and modern spectroscopic techniques. Result: Twelve compounds were isolated from the ethanol extract of A. membranaceus var. mongholicus

including β-sitosterol (1)

daucosterol (2)

formononetin (3)

oroxylin-A (4)

wogonin (5)

calycosin (6)

adenosine (7)

calycosin-7-O-β-D-glycoside (8)

(6αR

11αR)-9

10-dimethoxy-pterocarpan-3-O-β-D-glycoside (9)

astragalosideⅡ (10)

isoastragalosideⅡ (11)

D-3-methoxy-chiro-inositol (12). Conclusion: Compounds 3 and 4 were isolated from Astragalus membranaceus var. mongholicus for the first time.