A liquid crystal slit grating, including: a first grating substrate and a second grating substrate facing each other; a first polarizer being provided on a surface of the first grating substrate opposite to the second grating substrate; a second polarizer being provided on a surface of the second grating substrate opposite to the first grating substrate; and a plurality of photo spacers provided between the first grating substrate and the second grating substrate, wherein the first grating substrate includes a first substrate, a first electrode and a first alignment layer are sequentially formed on a surface of the first substrate facing the second grating substrate, and the first polarizer is provided on a surface of the first substrate opposite to the second grating substrate, the second grating substrate includes a second substrate, a second electrode and a second alignment layer are sequentially formed on a surface of the second substrate facing the first grating substrate, and the second polarizer is provided on a surface of the second substrate opposite to the first grating substrate, the liquid crystal slit grating comprising a nematic liquid crystal layer with twisted angle of 90 degree provided between the first grating substrate and the second grating substrate, wherein the second electrode includes a plurality of first stripe electrodes in parallel, the plurality of first stripe electrodes are provided on the second substrate at intervals,and the plurality of photo spacers are only provided at positions corresponding to the first stripe electrodes, and do not overlap with the interval areas between the first stripe electrodes, characterized in that polarization directions of the first polarizer and the second polarizer are parallel to each other; there is no other electrodes provided in interval areas between the first stripe electrodes; and the second alignment layer covers the first stripe electrodes and each interval area between the first stripe electrodes. a first grating substrate and a second grating substrate facing each other; a first polarizer being provided on a surface of the first grating substrate opposite to the second grating substrate; a second polarizer being provided on a surface of the second grating substrate opposite to the first grating substrate; and a plurality of photo spacers provided between the first grating substrate and the second grating substrate, wherein the first grating substrate includes a first substrate, a first electrode and a first alignment layer are sequentially formed on a surface of the first substrate facing the second grating substrate, and the first polarizer is provided on a surface of the first substrate opposite to the second grating substrate, the second grating substrate includes a second substrate, a second electrode and a second alignment layer are sequentially formed on a surface of the second substrate facing the first grating substrate, and the second polarizer is provided on a surface of the second substrate opposite to the first grating substrate, the liquid crystal slit grating comprising a nematic liquid crystal layer with twisted angle of 90 degree provided between the first grating substrate and the second grating substrate, wherein the second electrode includes a plurality of first stripe electrodes in parallel, the plurality of first stripe electrodes are provided on the second substrate at intervals,and the plurality of photo spacers are only provided at positions corresponding to the first stripe electrodes, and do not overlap with the interval areas between the first stripe electrodes, characterized in that polarization directions of the first polarizer and the second polarizer are parallel to each other; there is no other electrodes provided in interval areas between the first stripe electrodes; and the second alignment layer covers the first stripe electrodes and each interval area between the first stripe electrodes.