A display device and a manufacturing method thereof are provided. The display device includes: a first array substrate, a first opposite substrate, a second array substrate and a second opposite substrate stacked in sequence; the first array substrate comprises a first overlap portion overlapping with the first opposite substrate, a first extension portion extending from the first overlap portion, and the second array substrate comprises a second overlap portion overlapping with the second opposite substrate, a second extension portion extending from the second overlap portion; a side, facing the second extension portion, of the first extension portion comprises a first control IC, and a side, away from the first extension portion, of the second extension portion comprises a second control IC; and a space between the first and the second extension portions is filled with a heat dissipation component at least in an area where the first control IC is.