A novel two-stage buckling-restrained brace (TS-BRB) has been proposed to enhance the performance of conventional buckling-restrained braces (BRB), in particular to address the problem that conventional BRB cannot provide lateral resistance and energy dissipation capacity to the structure after failure under the action of major-after shocks. The energy dissipation unit of the TS-BRB consists of three Q235 steel plates in series with a tapered cross-section along the longitudinal axis. The energy dissipation section in the middle plays the role of energy dissipation first during the earthquake, and if this section breaks, the limiting slot in the restraint unit ensures that the rest of the energy dissipation section keeps working, giving the TS-BRB a higher energy dissipation capacity than conventional BRB. The slip distance of the TS-BRB is limited by varying the length of the limit slot, enabling the brace to meet the requirements of structural damping design. Test results demonstrate that the hysteresis curve of the TS-BRB is saturated and the shape of the hysteresis curve is consistent with theoretical expectations. The TS-BRB exhibits an obvious two-stage energy dissipation characteristic, with the end energy dissipation section continuing to operate after the middle energy dissipation section breaks. The additional accumulated energy dissipation after fracture is 138.41% of that before the fracture. The TS-BRB provides a solution to the problem of conventional BRBs losing load-bearing and energy-dissipation capacity immediately after fracture and offers greater energy dissipation reserves for the structure. Finally,a numerical model was established in ABAQUS,which demonstrates that the hysteretic curve of the numerical simulation agrees well with that of the experiment.