Aronia melanocarpa, as a natural medicinal plant, has been widely proved to have a variety of biological activities used as a novel food and medicine. Aronia melanocarpa polysaccharide (AMP) is the main component of the Aronia melanocarpa. The purpose of this research is to evaluate the delay and protection of AMP on aging mice by D-galactose (D-gal) induced, and to explore the effect of supplementing AMP on the metabolism of the intestinal flora of aging organisms.The aging model was established by intraperitoneal injection of D-gal (200 mg/kg to 1000 mg/kg) once per 3 days for 12 weeks, and administer AMP (100 and 200 mg/kg) were given daily by oral gavage after 6 weeks of D-Gal-induced.The results showed that AMP treatment significantly improved the spatial learning and memory impairment of aging mice through the eight-arm maze test, and H&E staining provedthat AMP significantly reversed brain tissue pathological damage and structural disorders.AMP alleviated inflammation and oxidative stress injury in aging brain tissue by regulating AMPK/SIRT1/NF-κB and Nrf2/HO-1 signaling pathways. Particularly, AMP reduced brain cell apoptosis and neurological deficits by activating PI3K/AKT/mTOR signaling pathway and its downstream apoptotic protein family.Importantly, 16S rDNA analysis indicated the AMP treatment significantly redarded the aging process by improving the composition of intestinal flora and abundance of beneficial bacteria. In summary, this study found that AMP delayed brain aging in mice by inhibiting inflammatory and regulating intestinal microbes, which providing the possibility for the amelioration and treatment of aging and related metabolic diseases.