A method of manufacturing an array substrate, an array substrate and a display device are provided. The method of manufacturing the array substrate includes: forming a pattern of a gate metal layer including a gate line and a gate electrode and preserving photoresist at a position on the pattern of the gate metal layer corresponding to a gate lead hole; sequentially forming a gate insulating thin film, a semiconductor thin film and a source/drain metal thin film; removing the photoresist preserved at the position on the pattern of the gate metal layer corresponding to the gate lead hole, and forming the gate lead hole; forming a pattern of a source/drain metal layer including a source electrode, a drain electrode and a data line and a semiconductor layer; and forming a pattern including a pixel electrode layer and a channel.