Abstract: The blue-green alga Anabaena sp. PCC7120 was grown in the medium containing 0.1 mol/L NaCl for 4 d and over 90% of cells became vacuola- ted. If they were grown in the common condition for over month, only a part of cells began vacuolation. The cultures were dropped on slide and a filter paper was put on the cover slip to absorb the surplus water. Alight pressure on the cover slip was made by a thumb to break some vacuolated cells. Some vacuoles were released from the vacuolated cells. The vacuoles were fully transparent, varied in size, they have not be showed under general microscope but under phase contrast microscope. Two kinds of cell vacuolations by salt inducing or by aging have parallelism.