Abstract: Polycystic ovary syndrome (PCOS) is one of the most common gynecological endocrine disorders. Most pathophysiological changes of PCOS begin in the peripubertal phase, and these pathophysiological changes will continuously affect women's health in the later stages of their lives. The pathogenic mechanisms of PCOS remain unclear, involving key aspects such as the regulation of hypothalamic-pituitary function, ovarian cellular functions, androgen levels, and insulin resistance. Herein, we summarized the latest findings on the pathogenesis of PCOS from the perspectives of the genetic background, intrauterine development, neuroendocrine function, inflammatory factors, gut microbiome, and environmental factors. This review will help provide new ideas for a deeper understanding of the disease, as well as its clinical diagnosis and treatment.