In this paper, we have investigated the upconversion luminescence properties of Er<sup>3+</sup> doped and Er<sup>3+</sup>/Yb<sup>3+</sup> codoped potassium lithium tantalate niobate (KLTN) ceramics. The green, red, and near infrared upconversion photoluminescence properties are analyzed by the steady-state spectra under 980 nm laser excitation. We research the relationship between UC fluorescence integral intensity and Er<sup>3+</sup> / Yb<sup>3+</sup> concentration. We research the pump energy dependence of UC luminescence intensities, and summarize the changing trend for the slopes n with Er<sup>3+</sup>/Yb<sup>3+</sup> ions concentrations. Finally, we make steady-state rate equations to describe the power dependence behavior and the UC mechanism. The deduced results is consistent with experimental results.