A method for forming parallel metal interconnection structures includes the steps that a substrate is provided, and multiple parallel sacrificial grid electrodes are formed on the substrate; side walls are formed on the lateral walls around the sacrificial grid electrodes; a dielectric layer is formed on the substrate, and the sacrificial grid electrodes and the side walls are covered with the dielectric layer; chemical machinery polishing is performed on the dielectric layer, and part of the sacrificial grid electrodes and the side walls in thickness are removed through the polishing; the remaining side walls are removed to form grooves around the sacrificial grid electrodes; the grooves are filled with metal to form metal side walls; a hard mask layer is formed, and surfaces of the dielectric layer, the sacrificial grid electrodes and the metal side walls are covered with the hard mask layer, the hard mask layer is provided with a first opening and a second opening, and the first opening and the second opening expose the metal side walls which are distributed at the two ends of the sacrificial grid electrodes in the width direction; the exposed metal side walls are removed through etching along the first opening and the second opening, and therefore the remaining metal side walls form the parallel metal interconnection structures. The width of the metal interconnection structures and accuracy of the distance between the adjacent metal interconnection structures are improved.