The invention discloses a maintenance and debugging tool for a horizontal outdoor high voltage AC isolation switch. The maintenance and debugging tool comprises a vertically arranged base bracket, a pulley and a transition mounting plate. The trolley comprises a trolley plate and two sets of guide wheels. The trolley plate is fixedly connected with the lower end surface of the base bracket. The two guide wheel sets are symmetrically arranged on the two sides of the lower part of the trolley plate for sliding on two parallel guide rails. The transition mounting plate is fixedly connected with the upper end surface of the base bracket. The upper surface of the transition mounting plate is provided with a plurality of mounting plate threaded holes for fixedly mounting the isolation switch. The isolation switch can be mounted and fixed on the maintenance tool and can move on the guide rails of the maintenance platform so as to adjust the foot distance.