Abstract: To solve the problem that the non-floored steel frame unit with crossed braces for functional reasons has poor seismic behavior in large power plant, two specimens were designed and processed according to one part of frame on the 3^rd-floor from a large-scale power plant. One of them was a frame with crossed, conventional H-sectioned braces(F-RB), and the other one was a frame with crossed buckling-restrained-braces(F-BRB). The pseudo-static tests on these two specimens were carried out to compare and analyze their seismic performance, including the hysteresis curves of horizontal load vs the displacement, the skeleton curves, the equivalent stiffness, the equivalent viscous damping ratio, etc. The features of deformation and failure of these two kinds of braces were studied. The following conclusions are drawn that under relatively large story drift ratio and with a failed beam, the earthquake-resistance capacity of F-BRB is apparently better than that of the counterparts of F-RB. Furthermore, F-BRB can steadily dissipate the energy. The beam without floor has adverse effect on the capacity of structure either resisting the earthquake or dissipating the energy. It is recommended that the beam's function of transferring load should be considered when the braces fail.