Abstract: It introduces the basic method and process of seismic performance assessment of RC frame structures with energy dissipation and isolated devices based on the FEMA P-58 theory. A typical multi-story RC frame structure is designed, based on which buckling restrained braces and isolation bearings are added to form a BRB-frame structure and an isolated frame structure. The finite element models of the three structures are established in OpenSees software. Appropriate seismic records are selected and scaled to analyze the structural responses of the three structures. The intensity-based assessment method in FEMA P-58 is used. The structural response and seismic loss results of the ordinary frame structure, BRB-frame structure and isolated frame structure under four seismic intensities levels (i.e., frequently occurred earthquake, design level earthquake, maximum considered earthquake, very rare level earthquake) are compared. The results of seismic performance assessment show that the use of either an isolated frame structure or an BRB-frame structure can effectively reduce the repair cost and repair time of the building under earthquakes. Compared with the ordinary frame, the repair cost and repair time of the isolated structure under rare earthquakes can be reduced by 65% and 58%, respectively, and those of the BRB-braced frame structure can be reduced by 47% and 34%, respectively.