Abstract: Existing corroded concrete structures may still be exposed to fire hazards. To study the shear performance of reinforced concrete beams under the combined effects of high temperature and corrosion, this paper produced nine corroded reinforced concrete beams. These beams were subjected to accelerated corrosion tests to achieve different levels of corrosion. Fire tests and post-fire shear tests were conducted on the concrete beams to investigate the effects of fire duration, stirrup corrosion rate and protective layer thickness on the shear performance of the concrete beams. A thermal-mechanical coupling model was established using ABAQUS, and a systematic parameter analysis was conducted to study the impact of fire on the shear performance of corroded concrete beams. The results indicate that fire duration and stirrup corrosion rate significantly affect the failure mode, residual load-bearing capacity and deformation capacity of reinforced concrete beams. Specifically, when exposed to fire for 2 hours or with a corrosion rate greater than 5%, the load-bearing capacity of the concrete beams decreases by more than 30%. Compared with the control beams, the effect of reducing the shear span ratio on improving the bearing capacity of the corroded concrete beams after fire is weakened. Finally, based on the finite element analysis results and existing shear load-bearing capacity calculation methods, a calculation model for the shear load-bearing capacity of corroded beams after fire exposure was proposed. This model can be used to assess the residual performance of existing corroded concrete beams after fire exposure.