Disclosed are an array substrate and a method for manufacturing the same, which belong to the technical field of display, and are able to solve the technical problem that the existing process for manufacturing array substrates is too complex. The array substrate includes a plurality of sub-pixel units formed on a base substrate. Each of the sub-pixel units comprises a thin film transistor and a second pixel electrode. An active layer of the thin film transistor is made of an oxide semiconductor. The second pixel electrode is made of a plasma treated transparent oxide semiconductor. The array substrate provided by the present disclosure can be used in an IPS or FFS liquid crystal display device.