A liquid crystal grating, a 3D touch display device and a driving method of the liquid crystal grating are provided. The liquid crystal grating including a first substrate; a second substrate, disposed opposite to the first substrate; a liquid crystal layer, filled between the first substrate and the second substrate; a touch electrode layer, located on a side of the first substrate that faces the liquid crystal layer; and a planar electrode, located on a side of the second substrate that faces the liquid crystal layer, wherein the touch electrode layer includes a plurality of strip-shaped electrodes parallel to each other and arranged separately at a set distance, and the strip-shaped electrodes in the touch electrode layer are divided into at least two touch electrode units that are not electrically connected to each other by a set rule of pattern division, for any one of the touch electrode units, when an external conductive object touches different positions of the touch electrode unit by way of single-point touch, variation of capacitance formed between the touch electrode unit and the external conductive object differs from one another.