A display processing apparatus is configured to process linearly polarized light emitted out from a display device. The display processing apparatus comprises a polarization conversion unit, wherein the polarization conversion unit is configured to convert the linearly polarized light into circularly polarized light in different rotation directions according to different display timings of the display device; the display timings include a first display time sequence point and at least one subsequent display time sequence point; a display signal corresponding to the first display time sequence point of the display device is a display signal of a first image, and a display signal corresponding to the subsequent display time sequence point is a display signal of a second image; and the polarization conversion unit converts linearly polarized light, emitted out from the display device during display at the first display time sequence point, into circularly polarized light in a first rotation direction, and convert linearly polarized light, emitted out from the display device during display at the subsequent display time sequence point, into circularly polarized light in a second rotation direction. A display system and a display method, which can greatly improve the confidential display effect, are further provided.