This paper describes an novel synthesis of D5-cypermethrin with D6-phenol (98% atom D) as the labeled precursor. D6-phenol was dehydrated by potassium deuterium oxide in anhydrous toluene, and then reacted with 3-bromobenzaldehyde to obtain the key labeled intermediate D5-3-phenoxy-benzaldehyde through Ullmann Condensation Reaction. Finally, D5-cypermethrin was obtained by “phase transfer catalysis cyanohydrins reaction” with sodium cyanide and 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarbonyl chloride by one-step method. The yield based on the amount of substance of deuterium-substituted phenol was 20%. As-synthesized product was con-firmed by MS, NMR and HPLC to be target compound. Its chemical purity is higher than 98%, and isotopic abundance is higher than 98% (atom D). This method could also be used to synthesize other labeled pyrethroids.