Two electrically controllable holographic polarization gratings are spatially multiplexed to serve as an image splitter for further stereogram application. An external AC voltage is used to modulate the diffraction efficiency of the fabricated holographic image splitter for the switching of a 3D stereogram and a 2D plane image. The polarization grating was generated by two writing beams with orthogonal circular-polarization state in dye-doped liquid crystal films. With proper experimental arrangements, a quasi single order diffraction was obtained and the other non-zero order diffractions were suppressed in this presented polarization grating. This characteristic leads to a good image contrast ratio for a stereogram. Finally, a switchable stereogram system using circular-polarization beam as backlighting was demonstrated successfully.