Abstract: Acording to the study on variations of the internal structure and the activeconstituent contents in the main roots of Astragalus membranaceus (Fish.) Bungeand A. membranaceus (Fish.) Bge. var mongholicus (Bge.) Hsiao, we found thatthe changes in the internal structure and the nutrient accumulation correspondedparticularly with their different rhythm of individual development. The contents ofthe two active constituents. Astragalaside Ill and total APS, also followed theirdifferent latvs of alternate vegetative growth and reproductive growth and positivelycorrelated with the nutrient accumlation and consumption trends;Furthermore, thecontents came to the summit before germination and after wilting.

Key words: Astragalus, Internal structure, Contents of active constituents