Traditional ball screw-type electromagnetic suspensions exhibit high rotational inertia, leading to large equivalent inertial forces during high-speed operation or on uneven road surfaces. This significantly degrades high-frequency vibration isolation, compromising ride comfort and system stability. To overcome this limitation, this study proposes an optimized electromagnetic suspension design incorporating a Series Stiffness and Damping (SSD) structure. A quarter-vehicle dynamic model is developed, and the system’s frequency response is analyzed using the mechanical admittance method. The suspension’s vibration isolation performance is further evaluated under both shock inputs and random road excitations through simulation analysis. The results show that the SSD suspension preserves low-frequency isolation while significantly improving high-frequency performance. Compared to the conventional electromagnetic suspension, the SSD configuration reduces the vehicle body’s peak acceleration from 7.4 m/s2 to 5.0 m/s2 under shock excitation, corresponding to a 36.3% reduction in peak load. Under random road conditions, the peak load is reduced by approximately 20%. This approach enhances impact resistance and system reliability, while offering a novel and effective solution to mitigate the adverse effects of equivalent inertial forces in electromagnetic suspensions.