Especially for young patients with premature ovarian failure, estrogen and progestin replacement therapy is very important. In fact, ovarian function is not permanent throughout a woman’s life; it always begins to decrease until it is completely lost at some point in a woman’s life cycle. This time period is the perimenopausal period of a woman. During perimenopause, the estrogen level in women’s bodies decreases rapidly, and about 2/3 of women will experience a series of symptoms caused by hypoestrogenemia of varying degrees, which is called “perimenopausal syndrome”; while only about 1/3 of women have no significant discomfort and can transition smoothly. However, for healthy women, perimenopause should occur after they have completed the unique physiological journey of menstruation, pregnancy, childbirth and breastfeeding, roughly between the ages of 45 and 55. Again, the result of a decrease in estrogen levels in the body is different for patients with premature ovarian failure, because this result is not a natural physiological process progression, but results from a pathological change in ovarian function. As a result, a series of symptoms similar to perimenopausal syndrome, such as hot flashes, sweating, irritability, low libido, vaginal dryness, etc., which should occur in women ten, twenty or even thirty years later, appear in the lives of women with premature ovarian failure at an inappropriate time. What are the consequences of lowered estrogen levels? In the near term, symptoms similar to perimenopausal syndrome, changes in female reproductive organs, breast atrophy, and skin changes, and in the long term, increased risk of cardiovascular disease, osteoporosis, and Alzheimer’s disease. If the problem is endogenous estrogen deficiency, then theoretically, supplementation by exogenous estrogen should be the correct treatment. For women with premature ovarian failure, this therapy is estrogen-progestin replacement therapy. However, the adverse effects on the body after taking estrogen for a long time have increased the fear of this therapy. In fact, part of the reason for the various adverse reactions that may occur in the body after taking estrogen does not necessarily lie in the exogenous estrogen itself: (1) whether the dose of hormone replacement therapy is close to the physiological dose and should last at least until the average age of menopause; (2) whether hormone replacement therapy is adapted to the body’s needs during different periods of illness, as different individuals may have different symptoms or pathological changes at different times; and (3) whether different individuals have different needs for (3) the applicability of different exogenous hormones to different individuals; (4) the doctor’s level of knowledge about hormone replacement therapy; (5) the patient’s compliance with medical advice; and so on. After the onset of premature ovarian failure, especially in young women, there is still a long way to go in life. From the perspective of improving the quality of life in the present and delaying the risk of long-term diseases, it is necessary to make a trade-off between the harm caused by low estrogen levels in the body and the adverse effects of taking exogenous estrogens on the body. The correct and intermittent administration of estrogen may do more good than harm to patients with premature ovarian failure. In conclusion, hormone replacement therapy remains the main treatment for endocrine disorders such as premature ovarian failure now and for a long time to come. This treatment is a long-term process and treatment must be individualized to suit different needs. During the treatment, the doctor should monitor the patient’s symptoms, signs and blood hormone levels in order to adjust the drug dosage at any time; while the patient should strictly follow the medical advice and obey the treatment, never take estrogen-based drugs without authorization; in order to protect the endometrium and reduce the incidence of endometrial cancer, progestogen must be taken at the same time.