There are very many reasons for low menstrual flow in the clinic, which must be combined with the patient’s specific clinical symptoms, signs and age stage to do the appropriate investigations to find out the cause and treat it symptomatically. There are several clinical possibilities: First, if a woman has low menstrual flow from the first menstruation, it is mainly considered to be caused by uterine dysplasia or endocrine disorders, such as infantile uterus, polycystic ovary syndrome and other diseases, which can be clearly diagnosed by checking sex hormone six and ultrasound. If the menstrual period is normal and the menstrual flow suddenly becomes less during the reproductive age, it is mainly considered to be caused by ovarian hypofunction, endometrial damage, endometrial adhesions, etc. The diagnosis can be clarified by examining sex hormone six, ultrasound and hysteroscopy. The sudden decrease in menstruation in women of childbearing age must also exclude abnormalities such as pre-miscarriage and ectopic pregnancy. Low menstrual flow in perimenopausal women is mainly considered to be caused by ovarian hypofunction, which is a normal physiological change and does not require special treatment.