Polycystic ovary syndrome (PCOS) is characterized by menstrual disorders, persistent ovulation disorders, hyperandrogenemia, hirsutism, obesity, infertility, insulin resistance and bilateral polycystic enlargement of ovaries, accounting for 30-60% of patients with anovulatory infertility. The main advantages include low price, ease of application, safety of use, low side effects, and low incidence of multiple follicle development. However, some patients may fail the CC and LE regimens and may need to choose other pro-ovulatory regimens. The Gn regimen is the second line of ovulation treatment for PCOS, and its cumulative ovulation effect is better than that of the CC regimen. It is based on the principle of obtaining effective developing follicles by increasing exogenous gonadotropins to bring follicle stimulating hormone (FSH) levels slightly above the threshold level for follicle initiation to initiate follicle growth and maintain follicle development. However, due to the endocrine disorder in the body of patients with polycystic ovaries, the ovaries have increased sensitivity to exogenous Gn, making the ovarian response difficult to control. Simply put, follicle development is stalled when low doses of Gn are applied, and once the dose is increased, the sensitive ovaries may recruit multiple follicles at once. This leads to multiple follicle development and even to ovarian hyperstimulation syndrome and the development of multiple pregnancies. In addition, high LH levels may result in decreased oocyte quality and immature follicles. Patients with PCOS have increased sensitivity to exogenous Gn, and often have hyperinsulinemia, obesity, and high LH levels, making it difficult to determine the most appropriate ovulation protocol. However, the response of the ovaries at the beginning of each cycle and the development of the follicles in the next cycle can be a great guide for the adjustment of the medication in the next cycle. In addition, studies have shown that adjuvant therapies such as weight loss, lowering LH and androgen (T) levels, and reducing insulin resistance can greatly improve the endocrine disorders in PCOS patients and increase the likelihood of successful ovulation treatment. Therefore, patients with PCOS should not be discouraged by the phenomenon of multiple follicles and immature follicles, as the performance of each ovulation cycle, whether successful or unsuccessful, will provide strong support for finding the most appropriate ovulation protocol.