An array substrate, a manufacturing method thereof and a display panel are provided. The array substrate includes a base substrate, a plurality of thin film transistors and a first light shielding layer. The base substrate includes a first surface and a second surface respectively located on opposite sides of the base substrate. The plurality of thin film transistors are disposed on the first surface of the base substrate, and each of the plurality of thin film transistors includes an active layer. The first light shielding layer is disposed on the second surface of the base substrate. The first light shielding layer has at least one opening that overlaps with at least one thin film transistor in a direction perpendicular to the second surface of the base substrate to allow light to irradiate at least the active layer of at least one thin film transistor.