A tile display device is provided. The tile display device includes a first tile substrate, the first tile substrate includes a first portion and a second portion. The tile display device also includes a second tile substrate, and the second tile substrate is adjacent to the first portion of the first tile substrate. A plurality of light emitting units disposed on the first tile substrate and the second tile substrate. A unit density of light emitting units of the first portion is defined as a first unit density, a unit density of light emitting units of the second portion is defined as a second unit density, and the first unit density is greater than the second unit density.