Abstract: To overcome the limitation of a single concrete material in achieving both favorable mechanical properties and effective fire resistance, a U-shaped composite beam consisting of recycled aggregate concrete (RAC) and high-strength concrete (HSC) was proposed in this study, referred to as the RAC-HSC composite beam. The fire resistance and bending behaviors before and after fire exposure of the RAC-HSC composite beam were studied, to comprehensively evaluate its performance under various conditions. The test results indicate that the fire resistance of the RAC-HSC composite beam was significantly superior to that of the HSC monolithic beam, exhibiting lower temperatures, reduced mid-span deflection, and fewer cracks, without any spalling phenomena under fire exposure. The yield load, load-bearing capacity and initial stiffness of the RAC-HSC composite beam were significantly higher than those of the RAC monolithic beam, approaching and even surpassing the bending performance of both normal aggregate concrete and HSC monolithic beams. Therefore, the U-shaped RAC-HSC composite beam represents a meaningful endeavor toward integrated design for the fire resistance and bending capacity of concrete components.