The invention discloses a display device with an extension plate, which comprises a display panel, an extension plate, a polarizing layer and a light shielding layer. The display panel has a first substrate and a second substrate; wherein the second substrate is at least partially overlapped with the first substrate and has a second end edge. The first substrate has a protruding section that protrudes beyond the second end edge and has a first end edge. The extension plate is disposed on the protruding section and has an inner end edge and an outer end edge; the inner end edge is opposite to the second end edge to sandwich the interface, and the outer end edge protrudes beyond the first end edge. The polarizing layer covers one surface facing away from the first substrate of the second substrate and extends beyond the second end edge to cover the extension plate. The light shielding layer is provided with a projection range at least partially covering the interface on the polarizing layer, the first substrate or the second substrate.