The invention relates to a jacking platform supporting power system hoisting dismantling method applied under the truss coverage working condition. The method comprises the steps that a jacking platform is jacked by one step pitch so that the jacking platform can break away from a supporting power system; a steel wire rope of a tower crane arranged in the vertical direction and a steel wire rope of a tower crane arranged in the side direction are connected with a to-be-dismantled component of the supporting power system vertically and slantly from the position over the supporting power system and at one side of the position above the supporting power system correspondingly; the relative height positions of a hook of the tower crane arranged in the vertical direction and a hook of the tower crane arranged in the side direction are controlled so that the to-be-dismantled component can be completely loaded onto the tower crane arranged in the vertical direction and then to be converted gradually to be completely loaded onto the tower crane arranged in the side direction, thus the to-be-dismantled component is gradually transversely moved out of the coverage range of a truss under the horizontal acting force applied by the tower crane arranged in the side direction, and hoisting dismantling operation of the supporting power system is completed. In this way, by means of the jacking platform supporting power system hoisting dismantling method, the problem that the supporting power system is covered with the truss, so that the supporting power system is difficult to dismantle is solved; and the method has the beneficial effects that high-altitude transverse movement of the to-be-dismantled component covered with the truss is achieved, the supporting power system is easy to dismantle, and dismantling work is easy to implement.