A method, equipment, and operation management system for detecting and authenticating a terminal in a passive optical network are provided. The method includes the following steps. The terminal has a logic registration code. A central office end receives the logic registration code sent by the terminal. The central office end judges whether the logic registration code of the terminal matches with the logic registration code stored at the central office end, and determines that the terminal is a valid terminal if the logic registration code sent by the terminal matches with the logic registration code stored at the central office end. The central office end records a terminal serial number from the valid terminal, and records a terminal identifier assigned to the valid terminal. By using the provided method, equipment, and operation management system, it is unnecessary to statically configure the terminal SN at the central office end, such that the maintenance cost of the central office end and the terminal is lowered, the flexibility of terminal detection and authentication is improved, and the maintainability of the central office end and the terminal is also enhanced.