Li et al.11 proposed a power train optimization method based on the genetic algorithm, which optimized the drive parameters of the motor while optimizing the transmission ratio, and they formulated dynamic and economical shifting rules. The results showed that when optimizing the transmission ratio and motor drive parameters, a selected performance indicator of the electric vehicle, such as the power, economy, or comprehensive performance, could be improved by formulating a proper shift schedule. Ahssan et al.12 proposed an energy-saving shift strategy suitable for complex road conditions, which minimized the energy consumption of electric vehicles without affecting their performances in complex road conditions. The pattern search method and gradient descent method were used to optimize the shifting schedule and transmission ratio in the Simulink environment. The results showed that the optimization could reduce power consumption, thereby increasing the driving range. Mortezeri-Gh et al.13 proposed an optimal shifting strategy for hybrid vehicles and optimized the transmission ratio of AMT parallel hybrid vehicles. The ADVISOR software was implemented using genetic algorithms to conduct joint simulations. The simulation results showed that the fuel economy of hybrid electric vehicles was significantly improved after the optimization. By formulating a proper shifting schedule, the drive motor of a pure electric passenger car equipped with a multi-speed transmission can operate in the high-efficiency state as much as possible, improving the vehicle’s power and economy. Therefore, it is of great significance to study the optimization of the transmission ratio under consideration of the shifting rules.