finite element model of the planetary gear transmission system and a parameter model of the planetary gear train were established, and finite element analysis modeling research on the planetary gear transmission system was conducted. Based on this, genetic algorithms were used to optimize the parameters of the transmission system, and simulation studies on the elastic behavior of the optimized transmission system were conducted under specific operating conditions to verify the rationality of the optimized system’s dynamic characteristics. The optimized planetary carrier pin hole node displacement is only 0.312 mm, resulting in minimal positional error. The maximum stress value of the third-stage planetary gear system after optimization is reduced by 0.45 MPa compared to before optimization, while the maximum strain value increases by 0.00058 mm/mm. The input angular velocity, planetary gear angular velocity, and output angular velocity of the optimized system can reach a steady state within the set time, with minimal deviation from theoretical values. The average simulated values of the meshing forces between the sun gear and planetary gears, and between the planetary gears and inner gear ring, are 2916 N and 1275 N, respectively, both close to the theoretical values. This study has preliminarily established an understanding of the transmission characteristics of planetary gear systems, providing a basis for optimizing the design of transmission mechanisms and power configuration in the main spindle drive units of CNC machine tools.