Abstract: Here, Li₃AlF₆ was adopted as a substitute salt for LiF-BeF₂ to study its pyrohydrolysis behavior in the mixed molten salts. Different molar rations of Li₃AlF₆ was firstly prepared, with its structure being characterized using X-ray diffraction (XRD), raman spectroscopy, thermogravimetry (TG), and differential scanning calorimetry (DSC) respectively. The pyrohydrolysis behavior of Li₃AlF₆ was carried out on our self-made apparatus. The results indicate that Li₃AlF₆ with different crystal structures can be synthesized by varying the conditions like temperature and LiF/AlF₃ molar ratio. LiAlO₂ in the absence of F^- ions is confirmed to be the pyrohydrolysis product of Li₃AlF₆, indicating that the complete conversion of the fluorides into the corresponding oxides, which can provide fundamental information for the following experiments in the aqueous-reprocessing process.