In order to change the undamped state of traditional helical spring, a helical spring with improved damping characteristics is developed by using Fe-Mn alloy. Firstly, the optimum process parameters of Fe-Mn alloy material for making helical spring is studied. Then, the Fe-Mn alloy helical spring is prepared and processed with optimized parameters to achieve high damping properties. Finally, the damping properties of Fe-Mn alloy helical spring is studied through the functional principle and analytical model of the helical spring. The results show that the Fe-Mn alloy helical spring exhibits a significant energy dissipation effect compared with the 65Mn helical spring under the same external excitation conditions. At a certain loading displacement, the loss factor of Fe-Mn alloy helical spring increases exponentially with the increase of displacement, while its equivalent stiffness decreases linearly, exhibiting pronounced softening characteristics. Specifically, when the equivalent strain amplitude of Fe-Mn alloy helical spring is less than 0.3%, its energy dissipation can be predicted using its torsional strain energy, providing a theoretical basis for spring design. This study provides a new direction for the development and application of vibration isolation products.