Provided are an optical relay system and a method for setting identification information of a remote device in an optical relay system. In particular, provided are an optical relay system and a method for setting identification information of a remote device in an optical relay system in which a donor device generates unique identification information of a remote device based on temporary identification information and characteristic information received from the remote device to automatically set identification information of the remote device, and as a result, the optical relay system can be normally implemented rapidly in initial installation of the optical relay system or a change of an optical relay system environment and convenience of a manager and reliability of a mobile communication service can be improved.