A high optical quality erbium-doped LuYAG single crystal has been grown by the Czochralski technique. The segregation coefficient of ${\mathrm{Er}}^{3+}$ was measured to be 1.05. The absorption and emission spectra were measured at room temperature. The spectroscopic parameters were calculated using the Judd–Ofelt (J-O) theory, and the J-O parameters ${\mathrm{\Omega }}_t$ ( $t=2$ , 4, 6) were found to be $0.89\times {10}^{-20}$ , $1.64\times {10}^{-20}$ , $1.23\times {10}^{-20}{\mathrm{cm}}^2$ , respectively. The emission cross section of the ${\mathrm{Er}}^{3+}$ ${}^4{I}_{13/2}\to {}^4{I}_{15/2}$ transition were calculated by the Fuchtbauer–Ladenburg formula, and the room-temperature fluorescence lifetime of the ${\mathrm{Er}}^{3+}$ ${}^4{I}_{13/2}\to {}^4{I}_{15/2}$ transition was measured to be $9.9\mathrm{ms}$ . Finally, promising laser performance with Er:Yb fiber laser pumping is described.