Tb³⁺, Tm³⁺, and Dy³⁺-activated SrY₂O₄ phosphors have been prepared via Pechini-type sol–gel method. X-Ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), photoluminescence (PL) and lifetimes, as well as cathodoluminescence (CL) spectra were used to characterize the samples. Under low-voltage electron beam excitation, the Tb³⁺-doped samples show a green luminescence, with a better CIE coordinates and higher emission intensity than the commercial product ZnO: Zn. Blue and yellow emissions could be obtained by doping with Tm³⁺ and Dy³⁺, respectively. A color-tunable emission in SrY₂O₄ phosphors can be realized by co-doping with Tm³⁺ and Dy³⁺. White cathodoluminescence (CL) has been realized in a single-phase SrY₂O₄ host by co-doping with Tm³⁺ and Dy³⁺ for the first time with CIE (0.315, 0.333). Furthermore, the cathodoluminescence (CL) properties of SrY₂O₄: Tb³⁺/Tm³⁺/Dy³⁺ phosphors including the dependence of CL intensity on accelerating voltage and filament current, the decay behaviour of CL intensity under electron bombardment, and the stability of CIE chromaticity coordinate have been investigated in detail. The as-prepared phosphors might be promising for use in field-emission display (FED) devices.