Abstract: In order to study the influence of corrosion degree, thickness of concrete cover and fire exposure time on the residual flexural performance of reinforced concrete (RC) beams, 17 RC beams were designed and fabricated, and electrochemical accelerated corrosion tests, fire tests and four-point bending tests were carried out successively. Then considering the effect of concrete spalling on temperature field, degradation of mechanical properties of corroded steel bars after high temperature exposure, as well as degradation of bond strength between corroded steel bars and concrete after high temperature exposure, an ABAQUS model was established to calculate the temperature field and residual flexural load-carrying capacity of RC beams after fire. The research results show that when the corrosion degree is less than 0.091, one-hour fire exposure has limited influence on the residual load-carrying capacity of concrete beams. With the increase of fire exposure time, there is a significant decrease in ultimate bending capacity. For example, compared with the specimen unexposed to fire, there is a 29.8% reduction in ultimate bending capacity for the two-hour fire-exposed RC beam. For severely corroded beams where the corrosion degree is greater than 0.1, the bending load-carrying capacity decreases significantly even after one hour of fire exposure, with a reduction up to 31%. As the protective layer thickness increases, the attenuation rate of bending load-carrying capacity after fire slows down. For example, the corroded RC beam with 30 mm concrete cover thickness has an increase in ultimate bending load by 38% compared with the specimens with 20 mm protective layer after exposure to fire for 60 minutes. Finally, based on the calculation results for residual load-carrying capacity of corroded RC beams, and introducing reduction factors considering corrosion degree, fire exposure time and protective layer thickness, a simplified method for calculating the post-fire bending load-bearing capacity of RC beams was proposed. This study provides theoretical basis for the evaluation of residual performance of fire-damaged corroded RC structures.