Abstract: Embryo implantation is a process of endometrium accepting embryo. Human embryo implantation is consist of three-stage process： apposition， adhesion and invasion. Successful implantation requires a functionally normal blastocyst， a receptive endometrium， and adequate maternal-fetal interaction. A large number of molecular mediators and genes have been identified， but many new molecular mediators and genes were undiscovered. New functions of those moleculars and genes are investigated. Research on mechanisms of embryo implantation is conducive to the diagnosis and treatment of infertility.

Key words: Embryo implantation, Endometrium, Gene expression, Signal transduction, Embryonic and fetal development, Endometrial receptivity