Embodiments of the invention disclose an array substrate and a fabrication method thereof, and a display device. The array substrate comprises a plurality of pixel units disposed on a base substrate. Each pixel unit comprises a thin-film transistor region and a display region. A thin-film transistor structure is formed in the thin-film transistor region, and an organic light-emitting diode. The organic light-emitting diode comprises a transparent first electrode, a light-emitting layer, and a second electrode for reflecting light that are sequentially formed. A transflective layer is formed in the display region. A color filter film is formed in the display region and is disposed between the second electrode of the organic light-emitting diode and the transflective layer. The second electrode of the organic light-emitting diode and the transflective layer form a microcavity structure. The color filter films in the pixel units of different colors have different thicknesses.