Preparation method of semeglutide

The invention provides a preparation method of semeglutide, which comprises the following steps: by taking resin as a solid-phase carrier, sequentially coupling amino acids and dipeptide fragments from a C terminal to an N terminal according to a primary sequence of the semeglutide through a solid-phase synthesis method to obtain semeglutide full-protection resin, and cracking and purifying to obtain the semeglutide, the dipeptide fragment comprises a 7-8 dipeptide fragment, a 9-10 dipeptide fragment, a 12-13 dipeptide fragment, a 17-18 dipeptide fragment, a 21-22 dipeptide fragment, a 24-25 dipeptide fragment and a 34-35 dipeptide fragment, wherein the 7-8 dipeptide fragment is Boc-His (Trt)-Aib-OH, the 9-10 dipeptide fragment is Fmoc-Glu (OtBu)-G1y-OH, the 12-13 dipeptide fragment is Fmoc-Phe-Thr (tBu)-OH, the 17-18 dipeptide fragment is Fmoc-Ser (tBu)-Ser (tBu)-OH, the 21-22 dipeptide fragment is Fmoc-Glu (OtBu)-G1y-OH, the 24 The semeglutide prepared by the method disclosed by the invention is high in yie