Based on previous studies and Faraday's Law, time-varying models of the uniform corrosion of reinforcing bars, both before and after the onset of cracking of the reinforced concrete (RC) cover have been established by analyzing the processes and time-varying mechanisms of reinforcement corrosion caused by chloride ions. The influence of time-varying bond strength performance on the flexural capacity of RC structures is reflected by a time-varying corrosion effect coefficient. The relationship between this coefficient and corrosion depth and time is also given in this paper. A time-varying model for the flexural capacity of RC beams in a chloride environment over a whole life cycle was then produced based on the time-varying reinforcing steel material performance, the time-varying bond performance, and standard structural member design theory. Lastly, the model was verified by comparing experimental and model based calculated data. The model was shown to be fit for practical engineering application in predicting flexural capacity and consequently has the impact on structural safety for any future year during the structure's service life.