Nanoscale and bulk SrAl₂O₄∶Eu²⁺, Dy³⁺were prepared respectively by auto-combustion of citrate gelatin and high temperature solid state method. The crystalline structure was examined by X-ray diffraction(XRD). The current-voltage characteristic was measured with a Keithley source meter 2410. The VUV spectra were carried out with VUV spectrometer. The result showed that light irrad iation increased the current, which indicates that some electrons are excited to the conduction band of host lattice. VUV excitation spectrum of nanoscale SrAl₂O₄∶Eu²⁺, Dy³⁺shifts to the shorter wavelength relative to bulk material because it has narrower bandgap. As a result, the current of nanoscale material is weaker than that of the bulk one.