Abstract: In order to study the aseismic performance of corroded RC frame beams in coastal atmosphere, the accelerated corrosion test of 8 RC frame beams with shear span ratio being 2.6 and 5 were conducted by applying the technique of artificial climate accelerated corrosion, and the quasi-static test were then carried out to research the effect of corrosion degree and shear span ratio on the aseismic behavior of RC frame beams. The analytical results show that with the increase of the degree of corrosion, the more proportion of shear deformation of the specimens would be brought out in the damage state, and that the damage process would be more rapid and the ductility would be worse. In addition, with the increase of the degree of corrosion of the reinforcement, the strength, the deformation capacity and energy dissipation capacity of RC frame beams would be gradually reduced, especially for the frame beams with small shear span ratio. Therefore, the effect of reinforcement corrosion on the small shear span ratio was more serious. Meanwhile, the relationship between ductility coefficient, power ratio index and cumulative energy dissipation and shear span ratio and corrosion rate of corroded RC frame beams was fitted, which provides a theoretical basis for quantitative analysis of aseismic performance of corroded RC frame beams.