The process of preparing lithium bis(oxalato)borate (LiBOB) was studied by TG/DTA and XRD methods. Five DTA plots were obtained at five different heating rates. According to the DTA plots, the Ozawa integral method and the Kissinger differential method were employed in the study on kinetics of solid state reaction. The result showed that to increase the heat preservation time at 100–120°C was advantageous to the synthesis of LiBOB. The stages of solid state reaction for preparing LiBOB were analyzed by XRD method. The optimum conditions of synthesis LiBOB were first heat preservation at 100–120°C, and then heat preservation at 240–280°C.