A method for repairing a disconnecting signal line of a thin film transistor (TFT) array substrate including: providing a TFT array substrate with a disconnecting signal line; defining a through hole at an edge of an overlapping area of the repairing line and the disconnecting signal line; printing ink in the through hole, the ink completely covers the through hole, the ink contains a plurality of metal nanoparticles; and curing the ink to make the repairing line and the disconnecting signal line to be connected.