Third-generation aromatase inhibitors (AIs), anastrozole, letrozole, and exemestane, have become important treatment options for hormone-responsive, postmenopausal breast cancer patients, the prerequisite for which must be menopause or complete suppression of ovarian function. However, there is no consensus in the industry on how to define menopausal status, creating great confusion and resulting in the misapplication of AIs, which not only severely affects the efficacy, but also a few patients have experienced serious events in which pregnancy has occurred. Recently, many academic journals and experts have conducted in-depth studies on this issue, so that the criteria for determining menopause can be gradually unified and lay the necessary foundation for the rational clinical application of aromatase inhibitors. The criteria for defining menopause in breast cancer patients have not been unified for a long time, and even in the ATAC trial, IES031 trial, MA-17 trial and other important clinical trials that have been completed in recent years, the criteria for menopause are not small differences. Menopause criteria of the ATAC trial: 1, bilateral oophorectomy. 2, Age ≥ 60 years. 3, If the age is between 45 and 59 years, with an intact uterus and at least 12 months of amenorrhea. 4, If the patient has been amenorrheic for less than 12 months (including amenorrhea due to hysterectomy, hormone replacement therapy, chemotherapy), FSH must be at menopausal level. The criteria for menopause in the IES031 trial are on the simple side, age ≥ 55 years, amenorrhea for more than 2 years or amenorrhea for more than 1 year before diagnosis. The MA-17 trial was an extension of the trial after 5 years of adjuvant TAM treatment. The study’s criteria for menopause: 1. Age at least 50 years before starting 5 years of TAM. 2, Underwent bilateral oophorectomy despite being younger than 50 years of age at the time of starting TAM. 3, If younger than 50 years of age or pre-menopausal when starting TAM, but developed menopause during adjuvant chemotherapy or adjuvant TAM. 4. Any age but FSH and LH are at menopausal levels. From the above three important clinical trials on AIs, it can be seen that bilateral ovariectomy, age ≥ 60 years, age ≥ 55 years and amenorrhea for more than 1 year before diagnosis can be considered as menopause. For amenorrhea due to chemotherapy or endocrine therapy at age less than 55 years, although FSH and LH testing is recommended to define it, there is no clear statement on the frequency of testing, testing technique, or whether estrogen is tested. The recommendations of the 2006 NCCN guidelines for breast cancer regarding criteria for menopause are clearly influenced by the criteria for menopause in the above mentioned trials and are generally consistent with the above mentioned trial study criteria. Menopause can be defined by bilateral oophorectomy and age ≥60 years. If age is 20 pmol/L and gonadotropins are normal, triamcinolone, or triamcinolone combined with ovarian function depot, or AIs combined with ovarian function depot are recommended.