Li-Fi which is also known as Light Fidelity refers to 5G light Communication systems which uses light-emitting diodes bulb as a medium for high-speed data communication instead of WI-FI. Nowadays internet has become a serious demand, people are using Wi-Fi hotspot in all public places.In the epoch of internet, there is a continuous urge for faster, secure, and reliable wire-wireless connectivity in all fields, while wireless networks are more preferable in all domestic application in general. Li-Fi is a new digital communication may be a best and alternative to Wi-Fi in wireless communication. This paper proposes about what is Li-Fi Technology, working of Li-Fi, advantages and its applications. The Li-Fi technology was proposed by Professor Harald Hass in University of Edinburgh. Li-Fi has thousand-fold greater speed than Wi-Fi and provides greater security because the light is unable to penetrate through the walls, which propose a replacement era of wireless communication. The concept of Li-Fi is data communication is acheived on fast flickering of LED light, which is not detected by human eye but it can be received on photo diode receiver which converts the on-off state into binary digital data. It has gained an enormous popularity in two years of its invention. Such technology has brought not only greener but safer and cheaper way forward for communication.