Abstract: Based on the basic principles of metal mechanics, electrochemistry, and fracture mechanics， studies of the interaction mechanism of corrosion medium and fatigue load of dispassivated reinforcement in the concrete structure have been carried out in order to accurately calculate the service life of the corroded reinforcement. A dispassivated reinforcement corrosion rate model considering the elastic deformation, plastic deformation and electrochemical action is established under the conditions of fatigue loads. On this basis, the calculation model for corrosion fatigue stress intensity factor amplitude of the cylindrical reinforcement is developed. The theoretical model for corrosion fatigue cracking propagation threshold and a reinforcement corrosion fatigue crack growth model are quantitatively analyzed. The reinforcement service life prediction model with corrosive medium and service loads is developed. The service life of the corroded reinforcement in the fatigue condition is calculated. Accoding to the steel bar corrosion fatigue test data in the references, the models and the method of the service life prediction are validated and the calculated results of steel bar corrosion fatigue life agree well with the test data when pH=2.5~12. The influence law of the fatigue loads on the steel corrosion rate is revealed through calculation and analysis of the service life.