Abstract: The flexural performance of concrete beams reinforced with GFRP/steel wire composite rebar (GFRP: Glass Fiber Reinforced Polymer) is affected by the failure mode which is decided by the reinforcement ratio. Considering the importance of reinforcement ratio to the flexural performance, sixteen concrete beam specimens were designed. The test variables were concrete compressive strength and reinforcement ratio. Based on the test on simply-supported beams, the effects of concrete compressive strength and reinforcement ratio on failure mode, cracking capacity, ultimate bearing capacity, cracking spacing, cracking width, cracking depth, and deflection were investigated. The test results will provide references and theoretical basis for the determination of the calculation method of safe reinforcement ratio for concrete beams reinforced with GFRP/steel wire composite rebars.