Abstract. One of the de ciencies of diagonal (X) bracing is buckling under compressive load, hence not reaching the yielding threshold and being unstable. In this numerical study, the behavior of X-shape brace was investigated, which was modi ed by Carbon Fiber Reinforced Polymer (CFRP) plates that could absorb compressive force and make it stable. This innovative brace consisted of two separate steel plates connected by CFRP sheets to each other in the middle of the compressive element. Thus, these two parts were connected by epoxy resin and bolts. In this study, Finite Element Method (F.E.M.) was used to simulate the elements of steel and ber polymers by Abaqus software under cycle loading after designing of ber layers and connection type. Also, the numerical result was compared with the normal steel brace. The result showed that the innovative brace had more e ciency under seismic response. According to this output, ductility and energy absorption increased in the innovative model (CFRP-BR), but sti ness decreased as compared with the normal steel brace.