A 3D display device is provided. The 3D display device includes a display panel and a light source, the display panel including a first substrate and a second substrate, wherein, the light source is disposed on a side surface of the first substrate, and configured to emit light into the first substrate, wherein, light is propagated in the first substrate in a total reflection manner; the 3D display device further includes a light adjustment structure disposed on a surface of the first substrate facing the second substrate; the light adjustment structure is configured to adjust an emergent direction of light incident into the light adjustment structure from the first substrate, such that a first part of light emerging from the light adjustment structure is propagated in a left eye direction through a first display unit of the display panel, and a second part of light emerging from the light adjustment structure is propagated in a right eye direction through a second display unit of the display panel. Thus, a utilization rate and brightness of light can be improved, and a thickness of the display device is reduced.