Abstract: The simulative experiment was carried out for researching the degradation rule of shear strength,deformation,stiffness and failure mechanism of the reinforced concrete beams under the action of different persistent loading and freeze-thaw cycles and mixed aggressive solution. The conclusion indicate that persistent loading influence the shear capacity of RC beams observably,and the degradation of stiffness and ductility of RC beams arise in part from stirrup corrosion and concrete deterioration in shear-compression zone. Calculation mehtod of shear strength of RC beam under the alternative action of freeze-the cycles and mixed aggressive solution based on the experiment data was also proposed.