A ${\mathrm{Ce}}^{3+}$ ion-doped $\alpha \text{-}{\mathrm{NaYF}}_4$ single crystal of high quality is grown successfully by an improved flux Bridgman method under the conditions of taking the chemical raw composition of $\text{NaF}\text{:}\mathrm{KF}\text{:}{\mathrm{YF}}_3\text{:}{\mathrm{CeF}}_3$ in the molar ratio of $30:18:48:4$, where the KF is shown to be an effective assistant flux. The x ray diffraction, absorption spectra, excitation spectra, and emission spectra of the ${\mathrm{Ce}}^{3+}$-doped $\alpha \text{-}{\mathrm{NaYF}}_4$ single crystal are measured to investigate the phase and optical properties of the single crystals. The absorption spectrum of the ${\mathrm{Ce}}^{3+}\text{:}\alpha \text{-}{\mathrm{NaYF}}_4$ shows a strong band that peaks at the wavelength of 300 nm. The emission spectrum of the ${\mathrm{Ce}}^{3+}\text{:}\alpha \text{-}{\mathrm{NaYF}}_4$ emits an intense ultraviolet (UV) band at the wavelength of 332 nm under the excitation of 300 nm light. Two separated luminous bands of 330 and 350 nm, which correspond to the transitions $5d\to {}^2{F}_{5/2}$ and