The prevalence of type 2 diabetes mellitus (T2DM) has dramatically increased globally, and the antidiabetic effects and underlying mechanisms of the polysaccharides extracted from Fu brick tea (FBTP) were investigated in high-fat diet (HFD)/streptozotocin (STZ)-induced T2DM rats. Administration of FBTP at 200 and 400 mg per kg bw significantly relieved dyslipidemia (i.e. TC, TG, LDL-C and HDL-C), insulin resistance (IR) and pancreas oxidative stress (i.e. CAT and GSH-Px) in T2DM rats. Mechanistically, FBTP rescued the HFD/STZ-induced alterations in the abundance of Bacteroidota, Actinobacteriota, Proteobacteria and Firmicutes. At the genus level, FBTP notably increased the abundance of Ruminococcus, Lactobacillus and Lachnospiraece_NK4A136_group, but reduced the population of Prevotella and Faecalibaculum in T2DM rats. FBTP also significantly elevated colonic short-chain fatty acid (SCFAs) levels. Moreover, apparent changes in amino acid absorption and metabolism were observed upon FBTP intervention. These findings suggested that FBTP might alleviate T2DM by reshaping the gut microbiota and regulating intestinal metabolites.