Adopting accelerated corrosion method, the failure mode, stress strain curves, peak stress, peak strain, ultimate strain and elastic modulus of the prismatic concrete specimens damaged by rebar corrosion were studied experimentally. Results show that the failure of corrosion damaged concrete specimens is mainly caused by the instability failure of micro column. The corrosion induced cracks which are roughly parallel to the direction of force are the main fracture surface. The measured stress strain curves of concrete damaged by corrosion are similar to that of uncorroded concrete, however, the slope of stress strain curve decreases gradually and the peak strain increases with the increase of corrosion ratio, the higher the corrosion rate of specimen is, and the more obvious the brittleness is. The peak stress of concrete specimens damaged by corrosion is lower than that of the uncorroded specimens, the peak strain and ultimate strain increases with the increase of corrosion rate, the elastic modulus decreases with the increase of corrosion rate. A stress strain constitutive model of concrete damaged by rebar corrosion is established, the calculated value of the model agrees well with the measured value.