The present invention provides a salt of a phenylpropionamide derivative and a preparation method therefor. The present invention specifically provides an acetate, hydrochloride, phosphate, citrate, benzoate, or fumarate of 4-amino-1-((2R, 5R, 8R, 14R)-2-(4-aminobutyl)-8-benzyl-5-isobutyl-4, 7, 10-trioxo-14-phenyl-3, 6, 9, 12-tetraazapentadecan-1-acyl)piperidine-4-carboxylic acid, and a preparation method therefor. The salt of the compound of formula (I) of the present invention has good stability, and the simple process thereof facilitates easy operation. The invention is better suited for clinical treatment.