Abstract: Plants are inevitably affected by a series of adverse environments during their growth. It is necessary for them to quickly perceive and adapt to the environment. Ca2+ is an extremely important second messenger in organisms and plays a significant regulatory role in plant growth，development and response to stress. The calcium-sensing receptor（CAS）is a specific protein located on the thylakoid membrane，which regulates the intracellular Ca2+ response by sensing the change of extracellular Ca2+ concentration，thereby affecting a series of downstream signal activities and making plants respond to the external environment. In this paper，we summarized the discovery process，structure，location of CAS in plants，as well as its influence on stomata opening and closing，participation in photosynthesis，and its important role in regulating stress response，so as to provide references for further studies on the biological functions of CAS in regulating stress response in plants.

Key words: Ca2+, extracellular calcium-sensing receptor, physiological function