Rocking walls offer advantages in controlling deformation modes and preventing weak-story failures. Step-terrace frame structures suffer from significant structural deficiencies, including irregular lateral stiffness distribution, abrupt changes in floor load-bearing capacity, and concentrated deformation in upper stories. To improve the yielding mechanism and mitigate unfavorable failure modes, a bottom-hinged rocking wall was introduced to regulate the structural response. Furthermore, to reduce seismic responses and limit residual deformations, a step-terrace frame-energy-dissipating rocking wall structural system incorporating buckling-restrained braces (BRB) was proposed. Numerical models of ordinary step-terrace frame structures, step-terrace frame-rocking wall structures, and step-terrace frame-energy-dissipating rocking wall structures were developed for a seismic intensity 7 region (0.15g) using OpenSEES. The reliability of the numerical models and material parameters was verified by simulating low-cycle reversed loading tests of step-terrace frame structures. Incremental dynamic analysis (IDA) was then performed to systematically evaluate the seismic fragility of the step-terrace frame-energy-dissipating rocking wall structure, considering IDA curve clusters, partition curves, seismic demand probability models, fragility functions, damage-state exceedance probabilities, fragility indices, collapse resistance reserve factors, and safety margin ratios. The results indicate that, under seismic excitations with the same peak ground acceleration (PGA), rocking walls effectively limit the development of structural plasticity, reduce response dispersion, and decrease the probability of exceeding various performance levels, thereby exhibiting enhanced collapse resistance. The incorporation of BRB further improves the seismic performance and collapse resistance of the rocking wall-frame system. Among the investigated 3 kinds of structures, the step-terrace frame-energy dissipating rocking wall structure exhibits the best seismic behavior and collapse performance, while the conventional step-terrace frame structure shows the poorest performance.