A method for preparing high-branch low-aromatic oligopeptides belongs to the technical field of separation and purification. The preparation method adopting dry vegetable protein powder as a raw material comprises the following steps: preparing a vegetable protein alkaline protease hydrolysate, preparing an aromatic amino acid hydrolysate with a C end, preparing a C end-removed aromatic amino acid hydrolysate, preparing an ultrafiltration separation liquid, preparing an aromatic amino acid-removed oligopeptide solution, preparing high-branch low-aromatic oligopeptide freeze-dried powder, and preparing a regenerated macro-porous adsorption resin column to prepare the high-branch low-aromatic oligopeptides with the F value reaching up to 21-26. Macro-porous adsorption resin of a styrene-based skeleton substitutes active carbon to separate aromatic amino acids and the aromatic amino acid-containing oligopeptides, so the method has the advantages of high separation efficiency, high precision and repeated use; the method adopting various modern chemical technologies and devices has the characteristics of convenience in operation, mild conditions, energy saving and low production cost; and the method realizes full utilization of the raw material, does not generate three wastes, is a typical green production process, and is convenient for being promoted and applied.