The invention discloses a brightening agent for leather, and a preparation method thereof. The brightening agent for the leather is prepared from the following formula components in parts by mass: 21to 29 parts of stearic acid, 14 to 19 parts of artemisia argyi oil, 25 to 28 parts of methylsilane, 20 to 24 parts of polyvinylpyrrolidone, 12 to 18 parts of almond oil, 24 to 30 parts of acetic acid,8 to 11 parts of mint stalk, 3 to 5 parts of inonotus obliquus extract, 15 to 20 parts of matt powder, 21 to 29 parts of phenoxyethanol, 18 to 27 parts of eugenia caryophyllus flower, and 8 to 17 parts of hydroxyethyl cellulose. The brightening agent for the leather provided by the invention has the characteristics of sterilization, static electricity and friction reduction, high brightness, elegance and fragrance.