The present invention provides an array substrate, a method for manufacturing the same and a display device. The array substrate includes a substrate; a anode layer and a pixel defining layer on the substrate; an auxiliary cathode layer on the pixel defining layer; a spacer layer on the auxiliary cathode layer; an organic light-emitting layer covering the anode layer, the pixel defining layer, and the spacer layer; a cathode layer covering the organic light-emitting layer, wherein the cathode layer laps with the auxiliary cathode layer on the pixel defining layer. Since the auxiliary cathode layer disposed on the pixel defining layer corresponds to the non-display area, the material with low resistivity can be selected for the auxiliary cathode layer. Thus the uniformity of the display brightness and the like of the screen can be improved, thereby improving the display quality of the screen.