The invention discloses a mechanical arm. The mechanical arm comprises a moving arm, a first adsorption device and a second adsorption device. The moving arm is horizontally arranged and moves in the horizontal direction or vertical direction to be away from or close to a first object to be adsorbed, and the first object is in tight contact with a panel; the first adsorption device is fixedly arranged on the moving arm and used for adsorbing the non-edge of the first object in contact with the first adsorption device under the vacuum effect; and the second adsorption device is movably arranged on the edge position of the moving arm, can vertically move in the vertical direction, is used for adsorbing the edge of the first object in contact with the second adsorption device under the vacuum effect, and can vertically move to enable the edge of the first object to be adsorbed, so that the edge of the first object is separated from the panel. Through the manner, adhesive force between the first object and the panel can be reduced, and it is ensured that the first object and the panel are separated very easily.