Embryo freezing is the storage of embryos in liquid nitrogen at -196°C. Frozen embryos can be transported in transport tanks containing liquid nitrogen. Frozen embryos are kept cold during transportation. Before transportation, the embryos in liquid nitrogen can be quickly placed in the liquid nitrogen transportation tank and then transferred, and after arriving at the destination, the embryos in the liquid transportation tank need to be promptly placed in the liquid nitrogen at the destination and then returned to the liquid transportation tank. Frozen embryos in the transportation process, the operation is more cumbersome, and need to be careful. The liquid transport tanks used in the transportation process are expensive, so the cost of embryo transfer is high. Therefore, if there is no special need, general companies or laboratories will not carry out the transfer of embryos.