Abstract: Taking the damage degree and reinforcement ratio of high-strength steel wire as test variables, the four-point bending performance tests of six flexural-strengthened RC beams with high-strength steel wire meshes reinforced engineered cementitious composites (referred to as HSWM/ECC) in load-carrying state and an ordinary RC beam were conducted to evaluate the flexural performance of strengthened RC beams. The flexural failure mechanism of strengthened RC beams in load-carrying state and the influence law of various influencing factors on the bending performance of strengthened beams were investigated. Research results indicate that the strengthening with HSWM/ECC in load-carrying state can significantly improve the yielding load, bearing capacity and ductility of RC beams. It can also effectively delay crack propagation and reduce the crack width. The larger the steel wire reinforcement ratio, the higher enhancement of yielding load, bearing capacity, ductility and crack-constraint effect of RC beams are brought by reinforcement layer. But this enhancement effect decreases as the damage degree of the original beam increases. On this basis, combined with the related theoretical analysis on mechanical behavior, this paper proposed the calculation formulas of the bearing capacity of flexural-strengthened RC beams with HSWM/ECC considering the effect of the secondary load.