Abstract: The normal menstruation depends on the intercoordination between the hypothalamus- pituitary- ovary system and the endometrium induced by ovarian hormone. Dysfunction of any aspect will result in amenorrhea，and then affect fertility. There are many causes of amenorrhea. The key of successful treatment is the clarified diagnosis. The overall diagnosis of amenorrhea should combine history，physical examination，endocrine and auxiliary examination. The most common causes of amenorrhea are hypothalamic amenorrhea，polycystic ovary syndrome，hyperprolactinemia and premature ovarian failure. This review discussed the etiological diagnosis of amenorrhea.

Key words: Amenorrhea, Oligomenorrhea, Polycystic ovary syndrome, Ovarian failure, premature, Pituitary neoplasms, Hyperprolactinemia, Adenoma