A 3D display panel, comprising: a lower substrate, comprising a plurality of columns of subpixels in which preset columns of subpixels which are in an OFF state serve as a buffer zone; a grating, comprising a plurality of aperture areas and a plurality of shielding areas, which are configured to allow images of one part of subpixels in the lower substrate to enter a left eye of a viewer, and allow images of the other part of subpixels in the lower substrate to enter a right eye of the viewer; and a positioning unit configured to determine a first distance which the viewer moves, and determine whether any subpixel of non-buffer zone is shielded by the grating according to the first distance; characterized in that it further comprises an adjusting unit configured to adjust the buffer zone when the any subpixel of non-buffer zone is shielded by the grating, so as to avoid the decrease of brightness or the occurrence of color cast in the 3D image seen by the user, in that two buffer zones are separated by a distance of P columns of subpixels in the lower substrate, and each buffer zone comprises Q columns of subpixels, each aperture area of the grating allowing an image with a width of P columns of subpixels in the lower substrate to enter into the viewer's eyes, and each shielding area of the grating shields an image with a width of Q columns of subpixels in the lower substrate, P and Q being positive integers, and Q≤P≤2Q; and in that in response to determining that J columns of subpixels of non-buffer zone are shielded by the grating, the adjusting unit is further configured to turn on corresponding J columns of subpixels in the buffer zone at a distance of P columns subpixels from the J columns of subpixels of non-buffer zone, wherein 1<J≤Q. a lower substrate, comprising a plurality of columns of subpixels in which preset columns of subpixels which are in an OFF state serve as a buffer zone; a grating, comprising a plurality of aperture areas and a plurality of shielding areas, which are configured to allow images of one part of subpixels in the lower substrate to enter a left eye of a viewer, and allow images of the other part of subpixels in the lower substrate to enter a right eye of the viewer; and a positioning unit configured to determine a first distance which the viewer moves, and determine whether any subpixel of non-buffer zone is shielded by the grating according to the first distance; characterized in that it further comprises an adjusting unit configured to adjust the buffer zone when the any subpixel of non-buffer zone is shielded by the grating, so as to avoid the decrease of brightness or the occurrence of color cast in the 3D image seen by the user, in that two buffer zones are separated by a distance of P columns of subpixels in the lower substrate, and each buffer zone comprises Q columns of subpixels, each aperture area of the grating allowing an image with a width of P columns of subpixels in the lower substrate to enter into the viewer's eyes, and each shielding area of the grating shields an image with a width of Q columns of subpixels in the lower substrate, P and Q being positive integers, and Q≤P≤2Q; and in that in response to determining that J columns of subpixels of non-buffer zone are shielded by the grating, the adjusting unit is further configured to turn on corresponding J columns of subpixels in the buffer zone at a distance of P columns subpixels from the J columns of subpixels of non-buffer zone, wherein 1<J≤Q.