Abstract: Objective: To investigate the beneficial effects of phenolic extracts of Rosa roxburghii Tratt. on obese mice induced by a high-fat diet. Methods: The intervention involved administering polyphenol extract at a dose of 400 mg/kg body weight per day to mice on a high-fat diet. The mice were orally gavaged continuously for 4 weeks, and various parameters such as body weight, liver index, histomorphological changes in white fat and liver tissues, serum biochemical markers, organ antioxidant capacity, and intestinal barrier function were examined. Results: In comparison to control group (CON), the MODEL group (MODEL) exhibited significantly (P<0.05, P<0.01) increased the level of insulin and inflammatory factors. The levels of high-density lipoprotein cholesterol (HDL-C) decreased in the four blood lipids, while the levels of total cholesterol (TC), triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C) significantly increased (P<0.01). The activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) in antioxidants were significantly reduced (P<0.01), the expression levels of intestinal barrier proteins and short chain fatty acids (SCFAs) were significantly reduced (P<0.01). In comparison to MODEL group, the polyphenol intervention groups (RF and RP) showed significantly decreased levels of inflammatory factors and oxidative stress (P<0.05, P<0.01), The activity of antioxidant SOD and GPx in the RF group was significantly increased, and the levels of ZO-1, Claduin-1, and SCFAs in the gut of both the RF and RP groups were significantly reversed (P<0.01). Conclusion: Prickly pear polyphenol extract effectively alleviated metabolic disorders in high-fat diet-induced obese mice in vivo, resulting in reduced body weight gain, protection against cellular changes in adipose and hepatic tissues, alleviation of inflammation and oxidative stress, and enhanced intestinal barrier function. Notably, the RF group showed a superior effect to the RP group.