Disclosed are an array substrate and a method for repairing broken lines thereof. By forming a via in an organic layer to correspond to each of the intersections between gate scan lines and source-drain data lines and depositing a second passivation layer in the via to form an aperture, a U-shaped long line can be directly laser welded to two of the apertures at two opposite sides of a broken site of one of the gate scan lines and source-drain data lines to recover connection between the two apertures of the broken line. This method saves an operation of removing an organic layer with laser and effectively reduces the machine laser loss in removing the organic layer so as to improve the repair efficiency and the repair success rate.