A three-dimensional (3D) display system is provided for displaying a 3D image. The 3D display system includes a display panel having pixels arranged at a pixel spatial period and a lens grating disposed together with the display panel. The lens grating further includes a plurality of lens units arranged at a first period and a plurality of non-lens units arranged at a second period. The second period is greater than one-third of the first period and less than two-thirds of the first period, and the plurality of lens units and the plurality of non-lens units are arranged such that the lens grating has a different spatial period from the pixel spatial period to reduce Moire fringe effect between the lens grating and the pixels of the display panel.