The invention discloses an evacuation rescue method based on accompanying lowering of a power transmission line under a power failure condition. The evacuation rescue method based on accompanying lowering of the power transmission line under the power failure condition comprises the steps that a rescue worker reaches a position above a wire where a trapped person is located by carrying two rescuemain ropes; the rescue worker sets an upside work station and a rescue rope passage; the rescue worker transfers the center of body weight to a position below the wire; the rescue worker descends to the position above the trapped person through a descending protector and locks the descending protector; one self protection rope is hung on a back hanging point of the trapped person, a force-distribution lifting set is connected to a main lock of the descending protector and the hanging point on a safety belt of the trapped person, the main lock is locked on the back hanging point of the safety belt of the trapped person under the condition that a short chain is hung in the descending protector and the hanging protection rope of the trapped person is released; and the rescue worker additionally arranges a friction lock at the brake rope end of the descending protector so as to descend to the round along with the trapped person at a constant speed through the descending protector, ground personnel cooperates with the rescue worker to make the trapped person at a W posture and then conducts prevention and treatment of safety belt hanging wounds, and thus rescue is completed.