Abstract: Disclosed are an etelcalcetide intermediate and a method for synthesizing etelcalcetide. The etelcalcetide intermediate is Fmoc-D-Cys(S—S—(N-Boc)-L-Cys(OtBu))-OH. The method for synthesizing the etelcalcetide includes the following steps: using N-Boc-L-Cqs-OtBu as a starting material to generate a primary product of a formula (A) by means of a substitution reaction, herein R is S-Py or Cl; and performing a coupling reaction on the primary product and Fmoc-D-Cys-OH amino acid to obtain Fmoc-D-Cys(S—S—(N-Boc)-L-Cys(OtBu))-OH. The key intermediate is used for synthesizing the etelcalcetide, which may improve the purity and the yield. It is important that the raw materials for synthesizing the key intermediate are cheap and readily available, and the process is simple.