Abstract: The Ca2+ messenger plays important roles in plant growth and development, as well as in plant response and adaptation to the environment. In this review, we analyze the regulation mechanism of Ca2+ in plant adaptation to low temperature, drought and salt stress, including (1) Ca2+ s ubcellular localization and distribution, homeostasis in intracellular Ca2+ at a lower level acting as the basis of Ca2+ signal oc currence; (2) Ca2+ signal molecular superiority and its signaling pathway ; (3) Cold acclimation and gene expression induced by Ca2+ signaling; (4) Physiological dormancy in over-wintering woody plants regulated by lasting high level of intracellular Ca2+; (5) Regulation of Ca2+ in drought and salt stresses; (6) Ca2+ signal in the regulation of stomatal closure/opening movement; (7) Roles of Ca2+ in the regulation of cell-wall thickening and strengthening under environmental stress.