A pixel unit, including: a pixel electrode, a gate electrode, a gate electrode line connected with the gate electrode, a source electrode, a data line connected with the source electrode, a second electrode disposed in a same layer as the pixel electrode, a first drain electrode connected with the pixel electrode, and a second drain electrode connected with the second electrode; the first drain electrode and the second drain electrode and the source electrode are provided with a channel therebetween, and the first drain electrode and the second drain electrode do not contact each other; along a direction of the data line, the edge of the second electrode is parallel with the edge of the pixel electrode and the two do not contact. An array substrate, a pixel driving method and a display device are further disclosed for overcoming the phenomenon of light leakage of the edge of the pixel unit caused by reduction of the width of the black matrix.