We propose a shift multiplexing method for a compact holographic volume storage system by using planar waveguide referencing. In the method, a planar waveguide is used to steer the reference beam and shift multiplexing is implemented by shifting the recording medium. We measure the diffraction efficiencies with respect to the shift distance of the medium for different widths of the waveguide. The selectivity of the storage system can be about 1.0 μm when the width of the waveguide is 0.05 mm. Multiple holograms are stored with a spatial separation of 2.5 μm. By using the planar waveguide, a high storage density can be achieved. As the planar waveguide is already commonly used in integrated optical systems, the whole storage system can become more compact and simpler.