High-voltage circuit breakers equipped with motor-operated mechanisms can enhance response speed and reliability. The requirement for rapid opening and closing operations imposes a design demand for high output torque and compact size on the driving motor. It is difficult to achieve an optimal balance between torque output and miniaturization of permanent magnet synchronous motors solely through magnetic circuit design, and parameter scanning optimization methods are computationally intensive and hard to implement. Therefore, this paper proposes a collaborative optimization method for torque output and miniaturization of the driving motor based on a response surface surrogate model. By conducting global sensitivity analysis to filter out input parameters with low sensitivity, the sample size is reduced and the model accuracy is improved. The response surface is constructed by calculating the undetermined coefficients using the least squares method to build a surrogate model, and the Pareto optimal solution set is obtained through the NSGA-II algorithm, with the accuracy of the model calculations verified by finite element methods, leading to the final optimized scheme. The comparison of simulation results before and after optimization shows an increase of 15.24% in rated output torque, 13.29% in peak torque, and a 12.22% reduction in motor volume, validating the effectiveness of this optimization method.