Abstract: The main factors of successful implantation of embryo include the ability to bed, the good receptive endometrium, the interaction of embryo and maternal. Endometrial thickness has been evaluated as a possible predictor of endometrial receptivity. Endometrial thickness in menstrual cycle can reflect the state of endometrial function. Adequate proliferation and secretory changes during the luteal phase is considered to be one of the prerequisites for successful implantation of the embryo. Reports have shown that a thin endometrium is closely associated with lower implantation rates. Furthermore, thin endometrium is an important cause of female infertility. It is important to look for the etiology, active treatment, and improve the endometrium receptivity. Pretreatment to the thin endometrium and increasing endometrial thickness to normal condition will help to improve the rates of pregnancy and live birth. However, the treatments of thin endometrium are not ideal at present. In this paper，we will review the definition，etiology and clinical treatment of thin endometrium.

Key words: Endometrium, Reproductive techniques, assisted, Fertilization in vitro, Embryo transfer, Therapeutics