The invention relates to the technical field of polypeptide synthesis, and discloses a method for preparing ularitide. The method includes the following steps that (1) full-protection linear peptide resin is synthesized; (2) splitting is performed to obtain linear peptide; (3) oxidation is conducted to obtain the ularitide; and (4) purification, salt rotation and freeze-drying are carried out to obtain the ularitide competitive product. By the adoption of the method, the process is simple, synthesis difficulty of the ularitide can be lowered, the yield of the synthesized ularitide is high, cost is low, the purity is 98% or above, and popularization is facilitated.