Abstract: Rebar corrosion is the main factor affecting the service performance of reinforced concrete (RC) structures. In this paper, taking RC beam as the research object, a three-dimensional multi-stage numerical model for shear analysis was established involving the non-uniform corrosion of reinforcement The non-uniform radial displacement was applied to concrete around the rebar to simulate the expansion of the corrosion products, then, taking the corrosion state as the initial condition, the static load was carried out to analysis the mechanical behavior of the RC beam. On the basis of verifying the rationality of the multi-stage numerical model, the corrosion effects of tensile reinforcement on the cover cracking and the performance degradation of the component were discussed; and the influence of shear-span ratio on the shear behavior of concrete beams without web reinforcement was analyzed. Finally, based on the simulation results, the calculation formulas of shear capacity in relevant design codes were discussed, and proposed a methodology for the prediction of the shear capacity of RC beams without web reinforcement.