The surface of highspeed and heavyduty brake disc needs to have high fatigue resistance and contact strength, and provides large frictional force during frictional contact. In order to achieve the above performance, a method of processing the surface of the brake disc by using an extrusion cutting process was proposed to obtain highquality contact surface. Based on the principle of extrusion cutting, a mechanical model of extrusion cutting was established. The common material Q345B of brake disc was used as test material, five factors including cutting speed, depth of cut, rake angle, clearance angle and edge arc radius were taken into account, the orthogonal test was carried out with surface roughness, residual stress and micro hardness as evaluation indexes. The signal-to-noise ratio (SNR) method and grey correlation method were used to optimize the multiobjective parameters, and the brake disc surface with good braking performance and long service life was obtained.