Estradiol is a type of estrogen and is the most predominant and biologically active hormone in estrogen. Estradiol is a steroid hormone that is mainly secreted by the ovaries, follicles, corpus luteum, and the placenta during pregnancy. Its clinical effects are mainly to promote the transformation of the endometrium into a proliferative phase, to promote the development of female secondary sexual characteristics, and to maintain the growth of female reproductive organs, breast glands, and other female characteristics, as well as the normal regular menstrual cycle. The clinical value of estradiol in blood and urine can be used to make clinical judgments, such as for the diagnosis of precocious puberty, female dysplasia, endocrine disorders and gynecological diseases. It is important to pay attention to a balanced diet and avoid rapid weight gain or loss to avoid disturbing endocrine hormone levels and affecting ovarian function.