Abstract: The cryopreservation technique of algae germplasm has been appreciated extensively. There are thousands of species or strains of fresh and sea water algae being cryopreserved in the world up to now. Most of them were preserved by the two-step freezing method. The procedure of the two-step method and the freeze-resistance of algae are two main factors influencing algal viability. The viability test is a key step in cryopreservation. Vitrification and encapsulation-dehydration are two new techniques and may have significant potential in the cryopreservation of some species of algae due to the limitation of the two-step freezing method.