The present invention provides an array substrate, a manufacturing method thereof and a display panel. The array substrate includes a substrate and an insulation layer provided on the substrate, the insulation layer including a via therein formed by etching. The insulation layer further includes a plurality of insulation sub-layers stacked on each other, and an insulation sub-layer among the plurality of insulation sub-layers which is farther away from the substrate has a larger etching rate under an etching condition for forming the via.