IVF, or in vitro fertilization-embryo transfer, as it is becoming known, has two very important components: one is controlled superovulation, where a certain number of eggs are obtained and fertilized with sperm in an in vitro dish to form fertilized eggs that are cultured into embryos; the other is embryo transfer. Embryo transfer is divided into fresh embryo transfer and frozen-thawed embryo transfer, both of which have their own advantages and disadvantages and are chosen clinically with a comprehensive consideration of the patient’s situation. With the development and maturity of embryo freezing technology, we can freeze the embryos obtained from in vitro fertilization and transfer them into infertile women at the right time, which can reduce the incidence of ovarian hyperstimulation syndrome (OHSS) and buy treatment time for women with poor endometrial conditions. This technique uses a highly concentrated cryoprotectant to treat the embryos, which rapidly cools the cells to a vitrified state both inside and outside the cells to avoid damage to the cells from the formation of ice crystals inside the cells. The embryos are then stored in liquid nitrogen (minus 196°C) to suspend the metabolism of the cells and maintain their pre-freezing state. The recovery rate of embryos by this technique can be close to 100%. Moreover, many studies have shown that the clinical pregnancy rate, live birth rate and pregnancy loss rate of frozen-thawed embryo transfer are not significantly different from those of fresh embryo transfer. Of course, deeper cytological and molecular studies need to be explored, and the technology will be improved. However, many patients still have doubts about freeze-thaw embryo transfer. There is no doubt that no technology is perfect and there are risks involved, but the use and value of any technology requires a combination of pros and cons, not an absolute judgment.