Embryo implantation is a complex physiological process,depending on synchronized embryo development to the blastocyst stage and differentiation of uterus into the receptive stage.Embryo can only implant in receptive endometrium,whereas uterine receptivity is only present in a limited period during pregnancy,known as "implantation window".The establishment of uterine receptivity involves morphological changes of luminal epithelium,as well as complicated regulation by steroid hormones and various cytokines.This review highlights the establishment of uterine receptivity and its molecular regulation.