Blastocyst is a broad concept that is divided into a certain time course, with stage 3 blastocyst, stage 4 blastocyst, and stage 5 blastocyst. When the blastocyst is transferred into the endometrium at the right time, it is able to obtain a successful pregnancy. Generally, in a fresh cycle, if a third day embryo transfer is not performed on the third day, we can try to perform an embryo transfer on the blastocyst on the fifth day; if the endometrial conditions are not available when the cycle, we will freeze this part of the blastocyst to allow the blastocyst to reach a dormant state. When the woman’s endometrial reserve meets our requirements and the endometrium is suitable for embryo implantation, we will resuscitate the blastocyst again and implant it into the woman’s uterine cavity. The transfer of blastocysts is the same as the transfer of embryos in other periods, that is, the better blastocysts will be transferred to the better endometrial environment and it will result in a successful pregnancy.