Method, equipment and system for diagnosing failure of passive optical network

The invention discloses a method, equipment and a system for diagnosing a failure of a passive optical network (PON). The method comprises the steps of: pre-obtaining identification information of each ONU (Optical Network Unit) in the PON, optical fiber link physical distance and the corresponding peak information of the ONU when the PON is normal; establishing a correspondence table of the identification information and the corresponding peak information of each ONU according to the obtained identification information and the physical distance parameter information of each ONU and the optical fiber link physical distance and the corresponding peak information of the ONU; obtaining corresponding peak information of optical fiber links of all current ONUs in the PON according to the preset failure diagnosis measure; matching the corresponding peak information of the current optical fiber link with the pre-stored leak information, and if corresponding peak position and/or amplitude changes, obtaining the identification information of the ONU corresponding to the changed peak according to the correspondence table; and if not, executing the equipment failure diagnosis. By applying the invention, the failure position can be immediately found and positioned, the failure maintenance time is shortened and the failure detection efficiency is improved.