Endometrial thickening does not refer to a specific disease, but is a description of the morphology of the endometrium. Physiological thickening of the endometrium prepares the uterus for conception and is therefore not harmful. However, pathological endometrial thickening is more harmful to women, for example, it may affect fertility, manifest anemia, irregular vaginal bleeding, menstrual disorders, and even shock and endometrial cancer. Under normal circumstances, the ovaries can produce eggs during the menstrual cycle and secrete both estrogen and progesterone, resulting in physiological thickening of the endometrium, and most women with physiological endometrial thickening have normal menstruation. If pathological endometrial thickening occurs, it means that the secretion of estrogen and progesterone in women’s body is abnormal, which may lead to menstrual disorders, irregular vaginal bleeding and a series of other symptoms, which are accompanied by the thickening of the endometrium, vaginal bleeding may be more or less frequent, and if the bleeding is excessive, it may cause blood loss anemia, and in serious cases, it may cause shock and endanger life. Especially in postmenopausal women, irregular vaginal bleeding with persistent thickening of endometrium may be a sign of endometrial cancer. Therefore, women with endometrial thickening should go to hospital for treatment as soon as their menstruation is abnormal.