This paper present results and discussions on an experiment study on the impact of corrosion ratio to the RC beams under fatigue and monotonic loads. Seven reinforced beams with the same steel type, concrete cover, steel diameter and ratio were test. The effect of corrosion ratio on flexural stiffness of these RC beams was discussed. Based on fatigue and monotonic test for these beams, the most investigated parameters in this experimental study were distortion, stress distribution, ultimate load of corroded reinforced concrete beams. The results indicate that the effect of corrosion ratio on flexural stiffness of RC beams is very obviously, curvatures of corroded beams increase monotonically with degree of corrosion. Fatigue loading has great impact on the performance of corroded RC beams; it can reduce the ultimate strength and ductility of the beams significantly as corrosion ratio increase.