Currently the prevalence of infertility among couples at childbearing age is on the rise in China with the average prevalence of 12.5%-15%, which is gradually becoming an important issue affecting the development of society. The polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women at childbearing age. Studies on female reproductive disorders always focus on PCOS, which is an important cause of infertility. The etiology of PCOS is complex and the pathogenesis is still unclear. As a complex endocrine metabolic syndrome, PCOS is closely associated with insulin resistance, chronic inflammation, and metabolic syndrome. The pathogenesis and pathological process of PCOS are correlated to the changes of gut microbiome. This paper reviews the research progresses of possible mechanisms of gut microbiome in the occurrence and development of PCOS.