Three corrosion degrees of reinforcement are chosen in this paper, which are considered to simulate minor, medium and severe degrees of corrosion in this field. A reinforcement mass loss about 5% is used to define a minor degree of corrosion, whereas mass losses about 10% and 20% are used to define medium and severe degree of corrosion, respectively. Fifteen specimens of the three corrosion degrees and seven uncorroded specimens are tested under fatigue. According to the results of the fatigue tests, using stress range as fatigue parameter and 50% as guaranteed probability, the fatigue S-N curves of the four different corrosion degrees of deformed reinforcement adaptable for fatigue reliability evaluation are put forward. These curves provide necessary principle for predicting the residual fatigue lives of aged existing reinforced concrete bridges.