ZaiGa₂O₄ thin film phosphors have been deposited using a pulsed laser deposition method on Si(100) substrates at a substrate temperature of 550℃ with oxygen of 100mTorr, and subsequently to investigate their photoluminescence characteristics after post-annealed at 600℃ and 700℃. As a result for X-ray diffraction, Ga₂O₃ shape appeared with increasing annealing temperature. The luminescent spectra show a broad band extending from 350 to 600nm peaking at 460nm. A post-annealing treatment of ZnGa₂O₄ thin films led to the different shape of luminescent intensity and grain size.