The present invention relates to a 2,2',4,4',6,6'-hexanitro diphenylethylene preparation method, which comprises that: (1) 2,4,6-trinitrotoluene and sodium hypochlorite are subjected to a reaction in a reaction solvent to prepare hexanitro bibenzyl, wherein the reaction solvent is a mixing solution of ethanol and benzene, and (2) the hexanitro bibenzyl and bromine are subjected to a reaction in a reaction solvent to prepare 2,2',4,4',6,6'-hexanitro diphenylethylene, wherein the reaction solvent is a mixing solution of dichloroethane and pyridine, the reaction solutions in the step (1) and the step (2) can be filtered to collect the filtrates, and the filtrates can be used as the reaction solvent of the corresponding steps. Compared with the preparation method in the prior art, the preparation method of the present invention has the following characteristics that: the coupling reaction solvents can be recycled, the solvent loss in the dehydrogenation reaction is less, and the pyridine consumption is less.