An array substrate and a method for fabricating the same are disclosed. The method for fabricating the array substrate comprises: forming a pattern of a gate electrode (2) and a common electrode (3) on a substrate (1); forming a pattern of a gate insulating layer (4), an active layer (5), a source/drain electrode layer (6) and a first passivation layer (7), wherein the first passivation layer (7) has a via hole and a thin film transistor (TFT) channel window, and the TFT channel window is located above the gate electrode (2); forming a TFT channel and a pixel electrode (9) with slits, wherein the pixel electrode (9) is connected to one of the source/drain electrode (6) through the via hole. The method is not only simple and stable but also improves the TFT quality.