In order to make rational use of waste cattle hair, the protein filler was prepared by using chitosan modified keratin which hydrolyzed waste cattle hair, then used in retanning and filling process. The optimal modification conditions of keratin: chitosan: keratin was 20:80, pH value was 2, time was 5h, chitosan modified keratin product zeta potential was 31.3mV, nanometer particle size was 482d·nm. Chitosan-modified keratin can be used as chrome auxiliaries in the retanning process to significantly reduce total chromium in the waste liquid. At the same time, the modified keratin had good filling performance. Moreover, the softness, tearing force and tensile strength of the shoe upper leather which filled with chitosan modified keratin were improved.