A privacy film, a privacy display system, a display substrate and a display device are provided. The privacy film includes a first electrode layer, a second electrode layer and an adjustment film layer between the first electrode layer and the second electrode layer. The adjustment film layer includes a plurality of first adjustment units and a plurality of second adjustment units alternately arranged along a first direction, the first adjustment unit has a width larger than that of the second adjustment unit in the first direction; and when the first electrode layer and the second electrode layer are powered on, the first adjustment unit has a light transmittance lower than a first threshold, and the second adjustment unit has a light transmittance higher than a second threshold, and the second threshold is larger or equal to the first threshold.