Abstract: The changes in Ca2+ localization in the leaf cells of Garyota urens L. under chilling stress were investigated with calcium antimonate precipitate-electromicros copic-cytochemical methods. When Garyota urens L. grew on the normal temperature, it was shown that the deposits of calcium antimonate being the indicator for Ca2+ localization mainly concentrated within the vacuoles and intercellular spaces and there was also some Ca2+ deposits in cell walls. But when Gar yota urens L. was treated by the temperature of 2℃ for 48 h, the level of Ca2+ increased in cytoplasm and plasma membrane, but decreased in vacuoles and intercellular spaces considerably. At the same time, the ultrastructure of chloroplasts suffered from chilling: the membrane of chloroplasts had been damaged, the layer of thylakoids was exiguous and unclear, the photosynthetic rate decreased evidently. And when Garyota urens L. was treated by the temperature of 2℃ for 120 h , the deposits of Ca2+ mainly concentrated within the cytoplasm, nucleus and plasma membrane and there was also some Ca2+ deposits in vacuoles, and the ultrastructure of some cells was simultaneously damaged severely: Chloroplasts structure, vacuole membrane and nuclear membrane had been damaged fully, the structure within the cell had become unclear, and the cell only have respiration. Thus it can be seen that there are some relations between the changes in Ca2+distribution within the cell and plant cold-hardiness.