Abstract: The hourglass steel rod damper made of LYP225 low-yield-point steel (LYP225-HBD) serves as an energy dissipation component in a structure to effectively enhance the seismic energy dissipation capacity of the structure and minimize the seismic damage of the main components of the structure. Initially, low-cycle reciprocating loading tests were conducted on two LYP225-HBD specimens. The LYP225-HBD exhibited stable, robust hysteresis curves, and remarkable energy dissipation capabilities. In the process of hysteresis and fatigue loading, the failure of the damper is mainly caused by the fracture due to the crack development of the energy dissipation section. Even after 30 cycles of loading at 11 times the yield displacement, the damper continues to function normally. All fatigue performance indicators met the relevant specifications in the fatigue loading process. The calculated formulae for initial stiffness and yield-bearing capacity aligned well with the experimental results, supporting the preliminary design and parameter optimization of LYP225-HBD. Using ABAQUS, a finite element analysis model was established, and its accuracy was validated through experimentation, with parameter analysis conducted on 15 LYP225-HBD models. The results indicate that the shape of LYP225-HBD significantly affects its bearing capacity, energy dissipation capability, and failure mode. As the ratio of the inner and outer diameters of the energy dissipation segment increases, the plastic development zone of the energy dissipation segment decreases, the energy dissipation capability diminishes, and the super-strong coefficient increases. It is recommended that the inner-to-outer diameter ratio be in the range of 0.45 to 0.55. With an increase in the length-to-diameter ratio of the energy dissipation segment, the bearing capacity, stiffness degradation coefficient, and energy dissipation capability of LYP225-HBD gradually decrease. The length-to-diameter ratio should be at most 4.75. The research results of this study can provide a reference for the practical application of LYP225-HBD in building structures.