A three-dimensional display including a display panel and a phase retardation film is provided. The display panel has a plurality of first pixel regions and a plurality of second pixel regions arranged in arrays. The phase retardation film is configured on a surface of the display panel. Here, the phase retardation film has a plurality of first retardation regions and a plurality of second retardation regions that are arranged alternately. The first retardation regions have the same phase retardation, the second retardation regions have the same phase retardation, and the phase retardation of the first retardation regions is different from that of the second retardation regions. All the regions of the phase retardation film have the same optical transmittance. A displaying method adaptable to the three-dimensional display is also provided.