This paper reports that polarized far-infrared reflectivity measurements have been done on LiGaO2 single crystal along two crystalline axes at different temperatures.The temperature dependent frequencies of the longitudinal and transverse optical phonon have been obtained from the real part of optical conductivity and the loss function respectively.A small Drude component is observed at frequency below 300 cm-1 which could arise from Li ions or oxygen deficiencies.The ionicity of LiGaO2 has been studied from the analysis of the Bo effective charge of different ions.