Abstract: To explore the absorption mechanism of APS-Ⅱ in vivo by establishing M cell model. First, Astragalus polysaccharides (APS) was divided into two different molecular weight polysaccharides APS-Ⅰ (> 2 000 kDa) and APS-Ⅱ (10 kDa) by ultrafiltration, and APS-Ⅱ (10 kDa) was prepared and fluorescently labeled. Meanwhile, M cell model was constructed by Caco-2 cells and Raji cells. The M cell model was treated with transport inhibitors to explore the transport of APS-Ⅱ on M cells. The results show that FITC has been successfully labeled to the end of APS-Ⅱ, and the M cell model was successfully constructed, which found that APS-Ⅱ could be transported by M cells, and four transport inhibitors of 5-(N-ethyl-N-isopropyl) amiloride (EIPA), genistein, dynasore and nocodazole indicated that APS-Ⅱ may enter cells through clathrin and caveolin-mediated endocytosis.