Corrosion behavior of reinforcing steel bars in mortar subjected to different magnitudes of tensile and compressive stresses was investigated with methods of open circuit potential（OCP）, linear polarization, and electrochemical impedance spectroscopy（EIS）. As the applied stress increases, the corrosion potential and impedance of the sample decrease. For the same stress magnitude, the samples under compressive stress show more negative corrosion potentials and lower impedance values than that experiencing tensile stress. Meanwhile, corrosion current density under compressive stress is much higher than that under tensile stress. EIS analysis shows that the destruction of the concrete/rebar interface under stress accounts for the degradation of corrosion resistance of rebar. Comparing with tensile stress, the same magnitude of compressive stress more severely destroys the concrete/rebar interface. Thus, the compressive stress more significantly aggravates corrosion of reinforcing steel bars.