An array substrate and a manufacturing method thereof, and a display device are provided. The array substrate includes: a first electrode, a second electrode and a light-emitting functional layer located between the first electrode and the second electrode. The light-emitting functional layer at least includes an organic light-emitting material layer of a first color and an organic light-emitting material layer of a second color, a color decay rate of the organic light-emitting material layer of the first color being greater than a color decay rate of the organic light-emitting material layer of the second color. The organic light-emitting material layer of the first color at least includes a first sub-layer and a second sub-layer arranged in a stacking manner, and a third electrode is disposed between the first sub-layer and the second sub-layer.