A gating and a 3D holographic display device are provided. The grating includes grating electrodes and spacing pillars disposed between a first substrate and a second substrate opposite to the first substrate. The grating electrodes extend along a first direction and are arranged along a second direction. Along a plane parallel to the first substrate, positions of spacing pillars are referred to as matrix points. The spacing pillars correspond to the matrix points; the matrix points include multiple first matrix point units arranged as an array. A minimum repeating unit of the matrix points includes four first matrix point units located at four vertices of a first quadrilateral. Two adjacent sides of the first quadrilateral are defined as a first unit vector and a second unit vector, respectively; and an angle between the first unit vector and the second unit vector is α1, and 0°≤α1≤90°.