Abstract: An overlay mark for concurrently monitoring alignment accuracy, focus, leveling and astigmatism and a method of application thereof are disclosed. The overlay mark comprises four inner bars and four outer bars formed at the corners of exposure areas. The inner bar has a sawtooth area and a bar-shaped area, and the outer bar is a fore-layer etched pattern. Both the inner bars and the outer bars are formed into rectangles, and each bar is one side of a rectangle and none of the sides are connected. The sawtooth areas of the inner bars disposed on opposite sides are located at a same position. The rectangle formed by the outer bars encloses the rectangle formed by the inner bars. During the monitoring process, a testing beam scans across a scan area being divided into two areas, i.e., one being the outer bars and the sawtooth area of the inner bars, and the other one being the outer bars and the bar-shaped area of the inner bars.