The preparation and luminescent properties of ZnGa2O4:Mn phosphors were investigated. A new multistage precipitation method, denoted as the chemical synthesis method, was developed for preparing Mn-doped ZnGa2O4. This method features a low temperature formation of phosphors with rod-type shape. The emission intensity of the phosphor prepared by the chemical synthesis method is stronger, by a factor of 3, than that of the phosphor prepared by the conventional method. The electron paramagnetic resonance study of ZnGa2O4:Mn indicated that the increase in emission intensity of the phosphor obtained by the chemical synthesis method might be due to a homogeneous distribution of Mn2+ ions in the host lattice.