Synthetic method of valsartan

The invention relates to a synthetic method of valsartan, wherein the valsartan is obtained by adopting 4-brooethyl-2'-cyanobiphenyl and L-valine methyl ester hydrochloride as starting materials and synthetizing via steps of coupling, acylating, azidation and hydrolyzing; in the steps of coupling and acrylating, the proper phase transfer catalyst is added to catalyst. In the synthetic method, the phase transfer catalyst is applied to synthetic process of the valsartan, thus, the reactants can contact each other fully; the reaction activity of the reactants is improved; the method has fast reaction speed, thorough reaction and high yield; compared with the method without the phase transfer catalyst, the yield of the target product valsartan can be improved by more than one time; the reaction time is notably shortened so as to further reduce manufacturing cost.