The invention relates to a method for purifying sulfur hexafluoride and a purifying and solidifying tank of the sulfur hexafluoride. The method includes: sucking the sulfur hexafluoride into a sulfur hexafluoride catabolite filtering air chamber through a compressor, adsorbing water, catabolite and toxic substances in the sulfur hexafluoride through special adsorbents, pressurizing and refrigerating the sulfur hexafluoride to liquefy the sulfur hexafluoride, enabling the liquefied sulfur hexafluoride to enter the solidifying tank, further cooling the sulfur hexafluoride through liquid nitrogen, and extracting foreign gases through a vacuumizing device when the temperature is lower than the solidifying point of the sulfur hexafluoride, wherein at this time, the sulfur hexafluoride is solidified, and impurity gases such as the air and carbon dioxide are still gases. The solidified sulfur hexafluoride melts when a heating device is started, and high-purity liquid sulfur hexafluoride is obtained, the liquid sulfur hexafluoride can be pumped out from a liquid outlet by utilizing a special compression mechanism and can be refilled or filled into a steel cylinder. The method for purifying sulfur hexafluoride and the purifying method have the advantages that the treatment efficiency is high, the treated gas is high in purity, the tail gas is free of pollution and the like.