A purification method of perfluoroisopropyl iodide, the specific is a method which separating perfluoroisopropyl iodide from a mixture containing perfluoroisopropyl iodide and hexafluoropropylene dipolymer, making the mixture contacted with at least one extractant which is choose from nitrile, ketone, alcohol and ester in the distillation process, making perfluoroisopropyl iodide separated from the mixture and to the second compound, the dipolar distance of mentioned extractant is more than 5.0*10<-30>C m, and then separating the perfluoroisopropyl iodide in the second compound by extractive distillation, getting the perfluoroisopropyl iodide containing almost no hexafluoropropylene dipolymer in turn. This invention changes relative volatility of perfluoroisopropyl iodide and hexafluoropropylene dipolymer azeotrope by adding suitable solution, carrying through the extractive distillation operation and getting high purity perfluoroisopropyl iodide.