The invention discloses a synthetic method of N-tertbutyloxycarbonyl piperazine and belongs to the field of drug intermediate synthesis. The synthetic method specifically comprises the following steps: firstly adding concentrated hydrochloric acid into anhydrous piperazine under ice bath so as to obtain piperazine dihydrochloride; mixing piperazine dihydrochloride and anhydrous piperazine so as to obtain piperazine monohydrochloride; and finally adding di-tert-butyl dicarbonate (Boc2O) into piperazine monohydrochloride to obtain a product N-tertbutyloxycarbonyl piperazine. In comparison with existing synthetic routes, the method of the invention has advantages of high conversion rate of raw materials, few generated impurity, simple post-treatment and the like.