An array substrate, a manufacturing method thereof, and a display device are provided. The array substrate includes a base substrate and a thin film transistor on the base substrate; a light shielding layer is disposed between the thin film transistor and the base substrate, and the light shielding layer includes a light shielding metal layer and, a light reflection adjusting layer which are stacked on the base substrate, the light reflection adjusting layer covers the light shielding metal layer, and a reflectance of the light reflection adjusting layer is lower than a reflectance of the light shielding metal layer.