In this paper, a series of Er∶CaGdAlO4 (Er∶CGA) laser crystals with different Er3+ doping concentrations (molar fraction) were grown by laser-heated pedestal growth method. The optical properties of the prepared series crystals were studied in detail. The maximum absorption coefficient, absorption cross section, full width at half maximum and radiation lifetime at the range of 780~840 and 955~1 020 nm in the absorption spectra were compared by combining the J-O theoretical calculation and optical characterization. In addition, the optical performance parameters of fluorescence emission spectrum such as emission intensity, emission cross section and energy level fluorescence lifetime were characterized and futher calculated. As a result, the optimal doping concentration of Er3+ is 5%. This work provides a certain experimental basis for obtaining a new type of laser gain medium which is expected to be used in 1.5~1.7 μm near-infrared band all-solid-state laser.