The invention discloses a preparation method of hexafluoro-1,3-butadiene. 1,1,2-trifluoroethenyl zinc bromide and a nonmetal oxidizing agent halogen are reacted in order to form hexafluoro-1,3-butadiene. The preparation method has the advantages of simple process, high reaction yield, low raw material cost, and small "three wastes (waste gas, waste water and industrial residue)"; hexafluoro-1,3-butadiene is suitable for preparing dry etching gas and the like.