The microstructure studies on Astragalus membranaceus var. mongolicus’vegetative organs were done with the method of plant anatomy and the officinal ingredients’ specific stored parts were ensured using the method of histochemistry. The results showed that: (1) the root of A. membranaceus var. mongolicus is composed of periderm and secondary vascular tissue. The secondary phloem is the main part of root, accounts for about 70% root transverse area, in which the secondary phloem parenchyma cells are the main ingredient. The stem of A. membranaceus var. mongolicus consists of three parts: epidermis, cortex and vascular column. Epidermis is composed of a layer of cells. Cortex is composed of dozens of layer of cells. Vascular column is ectophloic type, the arrangement is tight and pith ray is narrow. The leaves of A. membranaceus var. mongolicus are bifacial and include three parts: epidermis, mesophyll and vein. Vegetative organs of A. membranaceus var. mongolicus show droughtresistant characteristics. (2) Histochemical studies showed that saponins are stored in parenchymal cell of root, such as phelloderm, secondary phloem, dimensional root ray tube, forming layers, and its also stored in parenchyma cell of stem, such as cortex, forming layers and leafs mesophyll tissue and vein. Polysaccharides are mainly stored in parenchyma cell of root, such as phelloderm, phloem and dimensional root ray tube, as well as the leaf mesophyll tissue. Flavonoids are stored in the epidermis, cortex, collenchyma and pith ray cells of stem. (3) The quantitative analysis of ultraviolet spectrophotometer showed that the contents of saponins,flavonoid and polysaccharides in root, stem and leaf are consistent with the results of histochemistry. The results revealed that active constituent contents in root, stem and leaf of A. membranaceus var. mongolicus are higher, the stem and leaf of A. membranaceus var. mongolicus also have medicinal value and should be reasonable harvested and utilized.