Considering the high-speed and high power density technical specifications of new energy vehicle motors, there is a growing demand for rotor strength as motor peak speeds reach 20,000 r/min and beyond. The utilization of non-oriented silicon steel with a high yield strength in rotors has emerged as a promising approach to increase motor speed. However, the magnetic and mechanical properties of high-strength silicon steel under variable temperature conditions have not been fully explored, particularly in regards to their impact on motor torque, efficiency, and speed. This manuscript investigates the behavior of high-strength silicon steel before and after annealing and at different temperatures, analyzing its influence on high-speed motor performance. The validity and feasibility of this study are confirmed through prototype testing, providing a comprehensive reference for engineering design.