Abstract:Peptide YY （PYY） was a crucial gut hormone involved in appetite regulation and played a significant role in energy metabolism control. This paper systematically reviewed the structure， physiological functions， and regulatory mechanisms of PYY， with a particular focus on the mechanism by which gut microbiota stimulated PYY secretion via short chain fatty acid （SCFA） metabolic pathways. Research indicated that dietary fiber and other macronutrients could be fermented by gut microbiota to produce SCFAs （e.g.， acetate，butyrate）， which then activated intestinal L cells to promote PYY release， thereby enhancing satiety and inhibiting energy intake. Based on existing evidence， targeting the "dietary fiber-gut microbiota-SCFA-PYY"pathway was proposed as a potential intervention strategy for metabolic syndrome （such as obesity and diabetes）. Future research should integrate dietary fiber structural analysis with metagenomics techniques to develop personalized nutritional strategies， optimizing gut microbiota composition and PYY secretion， thereby offering to advance dietary interventions in metabolic diseases.