Abstract: The solubilities of KPF6，LiCl，and KCl in acetonitrile at -20~20 ℃ were measured by equilibrium method.Based on the solubility data，a new preparation technology of lithium hexafluorophosphate by transformation method was put forward.Using KPF6 and LiCl as raw materials，and CH3CN as solvent，after the transformation reaction and separation of the potassium chloride，by cooling，crystallization，recrystallization，drying of the solution，the high purity lithium hexafluorophosphate could be obtained.The sample was analyzed by infrared spectroscopy and X-ray diffraction，and compared with commercial lithium hexafluorophosphate，it could make a conclusion that the sample was pure lithium hexafluorophosphate with purity of 99.93%，and mass fraction of chloride ion of sample was 2×10-6，and the mass fraction of DMC insoluble was 0.06%， which were better than those of commercial one（purity of 99.90%） and met the requirements of Lithium Hexafluorophosphate and Lithium Hexafluorophosphate Electrolyte（HG/T 4066—2008）.Therefore，this method may replace the AHF method for the preparation of lithium hexafluorophosphate.

Key words: solubility, lithium hexafluorophosphate, transformation reaction