The method of impressed current accelerating corrosion was employed to obtain corroded steel bars and then the corroded steel bars were used in axial tensile fatigue testing. The impact of corrosion rate on the fatigue life of corroded steel bars and mechanical properties after steel bars being corroded were observed. Two uncorroded reinforcement specimens and fifteen corroded reinforcement specimens were tested under constant amplitude axial tensile fatigue loading. For convenience, the specimens were divided into six groups with reinforcement of average corrosion rates approximately at 0%, 3%, 6%, 9%, 12% and 15%. The results show as follows: The fatigue life of steel bars is obviously reduced as the result of reinforcement corrosion; a logarithmic linear relation exists between the stress magnitude and the fatigue life of the reinforcement specimens of different corrosion rates. Compared with uncorroded specimens, the fatigue life of corroded specimens drops about 5126%, 6084%, 6582%, 7104% and 7922% respectively, corresponding to tested corrosion rates of 387%, 678%, 947%, 1232% and 1535%; when stress amplitude is 200 MPa, the fatigue life of steel bars at stress ratio of 024 and 034 is reduced by 86% and 136% compared with that of steel bars at stress ratio of 010. The fatigue life of corroded steel bars attenuates with the development of corrosion by the exponential law approximately.