An Eptifibatide preparation method with product purity of more than 99.5%, the method comprising: using a solid phase polypeptide synthesis method to prepare eptifibatide resin, conducting acidolysis on the Eptifibatide resin to obtain a crude Eptifibatide linear peptide product, oxidizing to obtain a crude Eptifibatide product, purifying and exchanging salt to obtain an Eptifibatide finished product; the method using the solid phase polypeptide synthesis method to prepare the eptifibatide resin is: using a solid phase coupling synthesis method to sequentially splice a corresponding protective amino acid or a segment in the following sequence onto amino resin, and obtaining the Eptifibatide resin: X—Y-Trp(R1)-Pro-Cys(R2)-amino resin, wherein R1 is Boc or H, R2 is Trt or Acm, X is Mpr(R2)-Harg(R3), R3 is Pbf or H, and Y is Gly-Asp(OtBu).