A stereoscopic display device includes a display panel for displaying 2D/3D images, a driving circuit module, and a light-splitting device. The light-splitting device includes a first substrate having a plurality of first electrodes, a second substrate arranged facing the first substrate and having at least one second electrode, a liquid crystal layer placed between the first substrate and the second substrate, and a plurality of spacers in the liquid crystal layer. The driving circuit module is configured to, when in the 3D display mode, provide a plurality of driving voltages between the first electrodes and the second electrode to make the liquid crystal layer an array of liquid crystal lenses and, when in the 2D display mode, to provide a deflection voltage between the first electrodes and the second electrode to reduce a refractive index difference between the liquid crystal molecules and the spacers with a predetermined range.