The work aims to repair the worn high-speed train brake disc to reduce train operating cost. The CrMnFeCoNi high entropy alloy prepared with mechanical self-mixing powder by laser cladding was used to repair the brake disc and study the microstructure, composition phase, wear resistance and corrosion resistance. The best experimental technology was laser power of 1000 W, scanning speed of 5 mm/s, feeding voltage of 7.5 V, single channel width of 2.42 mm, single channel height of 0.44 mm and single overlap rate of 50%. There was burning loss in the process of laser cladding, so the powders composition was not equal to molar atom ratio and finally BCC and FCC phases were formed in CrMnFeCoNi high entropy alloy cladding layer. The casting microstructure of the cladding layer was uniform with the same growth tendency and certain amorphous and nanometer microstructures. The CrMnFeCoNi high entropy alloy reduced the wear by the friction factor of 0.3655, so the high entropy alloy cladding layer was more wear-resisting. The high entropy alloy cladding layer current density was 1.24?10?5 A/cm2 and the annual corrosion rate thickness was 0.146 475 mm/a. The high entropy alloy repair layer of high-speed train brake disc prepared by laser cladding has better wear resistance and corrosion than the matrix and the service life of worn brake disc is extended to meet the demand of brake disc.