The invention discloses a synthesis method for dextrorotation cefamandole nafate. The method includes the steps that in one-element organic solvent, 7-ACA and 1-methyl-1h-tetrazole-5-thiol are subjected to condensation with a boron trifluoride complex of the one-element organic solvent as a catalyst so as to generate 7-ATCA; and then, in another one-element organic solvent, under the effect of organic alkali, the 7-ATCA and S-(-)-formylmandeloyl chloride are made to react so as to generate the dextrorotation cefamandole nafate, then, an organic phase is left after hydrolysis and extraction phase splitting, organic acid sodium salt and another organic solvent indissolvable in dextrorotation cefamandole sodium are added, the dextrorotation cefamandole sodium is obtained through crystallization, finally, the dextrorotation cefamandole sodium is dissolved in water, organic solvent incapable of being dissolved in water is added together with organic or inorganic acid, an organic phase is left after extraction phase splitting, and reduced pressure rotary evaporation is conducted on the organic phase to obtain the dextrorotation cefamandole nafate. The method is simple, conditions are gentle, raw materials are easy to obtain, and purity of the finally-obtained product is 99% or above.