An array substrate, a manufacturing method thereof and a display device are provided. The array substrate comprises a plurality of gate lines (102) and a plurality of data lines (101); a region defined by adjacent data lines (101) and adjacent gate lines (102) is a pixel unit; the pixel unit includes a common electrode line (103), a pixel electrode (104), a thin film transistor (105) and an auxiliary electrode (202); a first end of the auxiliary electrode (202) is electrically connected with a drain electrode (203) of the thin film transistor (105); and a second end of the auxiliary electrode (202) is electrically connected with the pixel electrode (104). The array substrate is used for enhancing an electric field within the peripheral range of the pixel electrode (104) of the pixel unit and avoiding the phenomenon of light leakage at an edge of the pixel unit.