The invention discloses an electric insulator cleaning arm which comprises a first motor, a second motor, a cleaning head driving motor, a cleaning manipulator adjustable in posture, and a cleaning head. The cleaning manipulator comprises a pair of fixed arms, a pair of first movable joints and a pair of second movable joints, the fixed arms, the first movable joints and the second movable joints are sequentially connected, the fixed arms and the end portions of the first movable joints are hinged through a first wheel shaft, the other ends of the first movable joints and the end portions of the second movable joints are hinged through a second wheel shaft, the first wheel shaft and the second wheel shaft are controlled by the first motor and the second motor to rotate respectively, the cleaning head is movably connected on the free end portion of the second movable joints and connected with a rotating shaft of the cleaning head driving motor for driving through a spring shaft, the spring shaft is penetratingly arranged in a crack of the cleaning manipulator, a pressure sensor is arranged on the cleaning head and used for monitoring pressure applied on an insulator by the cleaning head, and a camera used for recognizing position of the insulator is arranged at a position, aiming at the cleaning head, on the second movable joints.