Array substrate, manufacturing method thereof, liquid crystal display panel and display device

The invention discloses an array substrate, a manufacturing method thereof, a liquid crystal display panel and a display device. According to the manufacturing method of the array substrate, after a first insulating layer is formed and before a source electrode is formed, it is not needed to form through holes which electrically connect the source electrode with an active layer through the composition process, but after a second insulating layer is formed and before a pixel electrode is formed, the composition process is conducted for forming a first through hole, a second through hole and a third through hole, the source electrode and the active layer are exposed, a first connecting portion is utilized for electrically connecting the source electrode with the active layer, wherein the first connecting portion and the pixel electrode are arranged on the same layer and insulated from each other, a second connecting portion is utilized as a drain electrode, wherein the second connecting portion and the pixel electrode are arranged on the same layer and electrically connected, and the second connecting portion is electrically connected with the active layer through the third through hole. Therefore, compared with manufacturing methods of existing array substrates, the composition process can be decreased by one time, and the array substrate manufacturing process can be simplified; in addition, the arrangement of the drain electrode can be omitted, thereby the aperture ratio of the array substrate can be raised.