An array substrate, a method for preparing the array substrate, and a backlight module are disclosed. Before electroplating a first metal layer on a pattern of a seed layer, the method further includes: forming a pattern of a compensation electrode wire electrically connected with a lead electrode on a side, where the lead electrode is formed, of a base substrate. The compensation electrode wire is at least on a second side of a wiring region, the pattern of the lead electrode is formed at a first side of the wiring region, and the first side and the second side are different sides. In the electroplating process, the lead electrode is connected with a negative pole of a power supply, the compensation electrode wire is electrically connected with the lead electrode, thus an area of an electroplating negative pole generating electric field lines is increased by utilizing the compensation electrode wire.