Preparation method of nesiritide

The invention relates to a preparation method of nesiritide, belonging to the technical field of preparation methods of polypeptide medicaments. The preparation method of the nesiritide comprises the following steps of: preparing nesiritide linear peptide resin through a solid-phase polypeptide synthesis method and carrying out acidolysis on the nesiritide linear peptide resin to obtain a crude nesiritide linear peptide product; and oxidizing the crude nesiritide linear peptide product to obtain a crude nesiritide product, and purifying the nesiritide crude product to obtain a pure nesiritide product, wherein the solid-phase polypeptide synthesis method is as follows: Fmoc-protected amino acids which correspond to the following sequences are sequentially connected into Fmoc-His(trt)-carrier resin through a solid-phase coupling synthesis method to obtain the nesiritide linear peptide resin, wherein only one-time or two-time solid-phase coupling synthesis reaction is carried out when a Ser(tBu)-Ser(tBu)-Ser(tBu)-Ser(tBu) fragment is connected. The preparation method disclosed by the invention has the advantages of product purity higher than 99.0 percent, single impurities less than 0.5 percent and remarkably enhanced product yield.