The invention discloses a high-speed dynamic balancing method and apparatus of an assembly type compressor rotor, and belongs to the technical field of rotor dynamic balancing. The high-speed dynamic balancing apparatus of the assembly type compressor rotor comprises a high-speed bearing and a high-speed dynamic balancing mechanism. The high-speed dynamic balancing mechanism comprises a stretching bolt, a taper reduction sleeve and a joint, the taper reduction sleeve is connected with a gearshaft and impellers, the stretching bolt passes through the taper reduction sleeve to be connected with the gearshaft, and the joint is connected with the taper reduction sleeve. The high-speed dynamic balancing method and apparatus of the assembly type compressor rotor effectively improve the rotor balance precision, the first-order critical rotation speed of the rotor is simple, and high-speed balancing can be carried out.