The present invention provides an array substrate and a manufacturing method thereof, and a display device. The array substrate comprises a base substrate, a metal pattern layer, a data line pattern layer, and a scan line pattern layer. Wherein, the data line pattern layer or the scan line pattern layer and the metal pattern layer are arranged in different layers and are directly connected to the metal pattern layer. So that the data line pattern layer or the scan line pattern layer and the metal pattern layer are formed a parallel structure. Because the resistance of the parallel structure is smaller than the resistance of the data line pattern layer or the scan line pattern layer, the resistance of the parallel structure when is used as a data line or a scan line, is reduced, thereby the display effect is improved.