Using light as input signal, optogenetics technology can precisely regulate the physiological functions of cells and has high specificity of time and space, which makes it possible to construct highly dynamic regulatory system. In recent years, with the discovery of novel photosensitive proteins and the innovation of light systems, the efficiency of optogenetics-based light control systems has been significantly improved. The application of light control system in bacteria is becoming more and more extensive. By using the lightcontrol system as an input module and combining it with other biological function modules, the regulation of gene expression, protein activity and bacterial physiological function can be realized. This paper mainly introduces the basic principle of optogenetics and its application in synthetic biology and the regulation of bacterial life activities.