Abstract: Photoinhibition of photosynthesis is a physiological stress that occurs in all plants, not only under high light stress, but also under other environmental stresses including low temperature, drought, flooding, salt stress and high CO2 concentration. In recent years, many research achievements have been reported on the nature and the mechanism of photoinhibition. In this article, the authors summarize the photoinhibition mechanism of Photosystem I (PSI) and Photosystem II (PSII); review the development of photoinhibition; analyze the defensive mechanisms against photoinhibition, e.g. heat dissipation, electron transfer, activated oxygen clearance, improved photosynthetic capacity and etc. Furthermore, the authors elaborate on the factors affecting photoinhibition, including the low temperature stress, light exposure intensity, water stress, salt stress, CO2 concentration and etc. Taken together, the authors discuss the problems and the future directions of the research.