A Passive Optical Network includes: an Optical Line Terminal, an Optical Distribution Network, and an Optical Network Unit or an Optical Network Terminal, wherein the Optical Line Terminal is adapted to exchange data with the Optical Network Unit or the Optical Network Terminal by using an optical module via the Optical Distribution Network, and the optical module is an optical module sending data in a continuous mode. Further, a method for data communication based on the Passive Optical Network includes: sending data by using an optical module sending data in a continuous mode; receiving the data by an optical module based on a set optical power threshold of data “0” and a set optical power threshold of data “1”.