A system and a method perform buoyance of a 3D hologram image on a hologram display screen in a projection mode. A system of displaying a digital hologram includes: a composite hologram unit configured to generate a hologram array by receiving hologram data of a fringe pattern and by compositing background image and a foreground image using the received fringe pattern; a hologram projection unit configured to project a hologram image through a wide-angle lens by applying a light to the hologram array; and a hologram display unit configured to perform space buoyance of the hologram image projected by the hologram projection unit on a 3D hologram display screen. The digital hologram content is managed in real time, and transmission of the digital hologram content to a remote place and site adaptive display of hologram image media may be achieved.