High-power electric spindle is the core and key functional component of large-scale machining center, their performance indicators directly determine the quality of CNC machine tools. This paper proposes an optimization design method for key components of High-power electric spindle. The rolling elements of the bearings, the inner rings of the bearings, the outer rings of the bearings, and the bearing cages are optimized to enhance the stability of the electric spindle shafting system. Simulation analysis and optimization design of the electromagnetic, thermal, and mechanical multi-physical field coupling of the electric spindle motor are carried out. By adopting advanced improved technological methods such as Four-stage carburizing and quenching, Three-stage centering hole grinding and finishing, and Five-stage nitride dehydrogenation, the prototype of the High-power electric spindle was finally developed. After third-party testing, the parameters of the developed electric spindle, such as rotational speed, torque, power, power factor, current unbalance degree, efficiency, temperature rise, radial runout accuracy of the electric spindle, end face runout accuracy, and radial runout accuracy of the inspection rod, have all reached the leading level in the industry.