The invention discloses a preparation method for punicic acid. The preparation method comprises the following specific preparation steps: mixing pomegranate seed oil with fatty acid; adding the obtained mixture into an organic solvent for dissolving; freezing the formed solution at a temperature of -30 to 10 DEG C for 0.5-2 h; if all the solution is frozen to a solid state, taking out a solid frozen product; placing the solid frozen product at room temperature, and fractionally collecting a melt, wherein a part that is melted out in later stage is a punicic acid-rich segment; and removing theorganic solvent in the punicic acid-rich segment to obtain high-purity punicic acid. The preparation method of the invention achieves the purpose of separation by using the difference in melting points of punicic acid and other fatty acids, and has the advantages of short production cycle, high yield, low cost, simple operation and the like.