The present disclosure relates to a display mode controlling device, a controlling method thereof and a display device. The display mode controlling device includes: a first substrate including a plurality of lens units arranged in an array, each of the lens units is provided with an annular diffractive phase grating; a second substrate aligned with the first substrate; a liquid crystal (LC) layer located between the first substrate and the second substrate; and a control electrode configured to generate a predetermined electric field to control a deflection state of a LC molecule.