Pharmaceutical raw materials hexafluoroacetone synthesis method, comprises the following steps : 3 mol 2, 3-dihydroxy-hexafluoroisopentane and 4-6 mol N-methylpropionamide were added to the reaction vessel, raised the temperature of the solution to 70-80癈 for 60-80 min, then added 2-3 mol bismuth molybdate, continued to react for 50-70 min, reduced the temperature to 40-50癈, vacuum distillation, collected the fractions of 80-89癈, washed with m-cresol solution, washed with m-chloroaniline solution, recrystallized in the methoxy toluene solution, and got the finished product hexafluoroacetone.