Using annual Astragalus membranaceus(Fisch.)Bge.var.mongholicus(Bge.)Hsiao (A. mongholicus) and Astragalus membranaceus (Fisch.) Bge (A. membranaceus) seedlings as materials, we used potting to simulate drought for 12 days and then resume watering. The effects of drought stress on the physiological status of A. mongholicus and A. membranaceus and the contents of calycosin7OβDglucoside and calycosin in the roots, stems and leaves were investigated. The results showed that: (1) drought stress significantly inhibited the growth of shoots in A. mongholicus and A. membranaceus, but had little effect on their roots. The relative water content of soil decreased after 4 days of continuous drought treatment, but the relative water content of the leaves of A. mongholicus and A. membranaceus decreased only after moderate drought stress (8~12 days of continuous drought), and the degree of decrease of A. membranaceus was larger than that of A. mongholicus. (2) Under drought stress, the activities of SOD and POD in the roots and leaves of A. mongholicus and A. membranaceus both increased first and then decreased, and the activities of SOD and POD in the roots and leaves of A. mongholicus were lower than that of A. membranaceus. (3) The content of calycosin7OβDglucoside in different organs of A. membranaceus was leaf> stem> root, while the content of calycosin7OβDglucoside of A. mongholicus in the roots, stems and leaves was not significantly different. The content of calycosin in A. membranaceus was expressed as leaf> stem, but in A. mongholicus, the opposite trend was found (stem>leaf). There are also differences between the content of flavonoids in the same organ of A. mongholicus and A. membranaceus. The drought resistance of A. mongholicus is higher than that of A. membranaceus. Moderate drought stress can promote the accumulation of calycosin7OβDglucoside and calycosin in the organs of Astragalus.