The invention discloses a method for pilot protection multiplex channel fault positioning. The method comprises the following steps: adding a byte for channel monitoring in a pilot protection multiplex channel transmission message, and defining an independent channel fault in a channel monitoring byte; monitoring the channel condition and forwarding a channel transmission message by each equipment in a channel; and modifying a channel monitoring byte when the equipment in the channel monitoring the channel fault, wherein the equipment in the channel can only modify the byte bit of the corresponding equipment channel fault point and continuously forwards a channel transmission message; issuing a channel fault point alarm through a protection device; restoring the channel monitoring byte through the equipment after the channel fault is restored, and returning the channel fault point alarming through the protection device. The fault positioning method disclosed by the invention can realize the fast positioning of the pilot protection multiplex channel fault point without damaging the original communication running state and environment, and the positioning of the channel fault point is realized without adding extra equipment.