Abstract: The corrosion influence on bond strength between reinforcement and concrete without stirrups is investigated in this paper. A theoretical model is proposed firstly, to calculate the ultimate bond stress of corroded deformed bar before corrosion-induced cover cracking. This model demonstrates quantitatively the mechanism of increment of bond strength between corroded reinforcement and concrete. Based on stress analysis for the concrete corbel between the ribs under the normal compressive pressure, friction pressure and corrosion pressure, an expression for the ultimate bond strength of corroded bars under splitting failure is deduced. The unknown parameters are determined such as friction coefficient, etc. The solution procedure is presented in detail. The results of this model are in good agreement with some other published experimental data.