Embodiments of the invention provide an array substrate, a manufacturing method thereof and a display device. The array substrate comprises: a base substrate; a gate line and a gate electrode formed on the base substrate; a gate insulating layer formed on the gate line and the gate electrode; a source electrode, a drain electrode and a pixel electrode formed on the gate insulating layer, wherein the pixel electrode is directly connected to the drain electrode; and an active layer formed on the gate insulating layer, the source electrode and the drain electrode.