Co-doped MgGa2O4 crystal was grown by solid-state sintering method. Growth of the Co-doped MgGa2O4 crystalline crystal was achieved by employing high-purity MgO and Ga2O3 powders, and the Co added as impurities was 1 mol%. Co-doped MgGa2O4 crystal growth was to use a high-temperature electric furnace having a temperature rising region from room temperature to 1500 ℃, was grown at 1350 ℃. The structure and composition of Co-doped MgGa2O4 crystals were analyzed by EDS (Energy Dispersive Spectrometer) and XRD (X-ray diffraction) measurements. XRD analysis revealed that Co-doped MgGa2O4 crystal adopt a cubic structure with respective lattice constants of a = 8.289 Å. The optical absorption spectrum obtained near the fundamental absorption edge showed that this compound has a direct energy band gap. The direct optical energy gap of the Co-doped MgGa2O4 crystal was given as Eg = 4.703 eV, respectively, at 293 K. The PL(Photoluminescence) spectrum of the Co-doped MgGa2O4 crystal was measured wavelength range 600 ~ 800 nm at 293 K, and a high intensity emission peak due to the Co2+ ion.