An array substrate and a display device are provided. A common electrode line with the same extending direction as a gate line is disposed at one end near a thin film transistor, and forms a storage capacitor with a drain electrode of the thin film transistor. As compared with the case in the prior art that a common electrode line and a thin film transistor in an array substrate are disposed at both ends of a pixel, respectively, and it is necessary to separately provide a storage capacitance electrode useful for forming a storage capacitor with the common electrode line, the pixel region occupied by the thin film transistor and the common electrode line can be effectively decreased. Thus, the aperture ratio is increased, and the display brightness of an IPS liquid crystal display device is enhanced.