Provided is a test structure for wafer acceptance test (WAT). The test structure includes a row of a plurality of first pads electrically connecting to each other, a second pad, a third pad, a first peripheral metal line, and a second peripheral metal line. The second pad is disposed in the vicinity of a first end of the row, wherein the second pad is electrically disconnected to the first pads. The third pad is disposed in the vicinity of a second end of the row, wherein the third pad is electrically disconnected to the first pads. The first peripheral metal line is disposed at a first side of the row and electrically connected to the second pad. The second peripheral metal line is disposed at a second side of the row and electrically connected to the third pad.