In order to explore the decay of salt-freeze-thaw resistance for reinforced concrete under freeze-thaw circumstances in cold regions, the paper adopted freeze-thaw experiment of saline solution to imitate the state of salt-freeze for reinforced concrete. By means of testing quality loss, the decay of dynamic Young′s modulus,change of transverse fundamental frequency, it evaluated the decay situation of reinforced concrete salt freeze thaw resistance.The result indicated that the curve of salt-freeze-thaw resistance's decay for reinforced concrete is just like power function curve of rank 4 square in the case of saline solution-freeze-thaw. As the influence of Cl- on transverse fundamental frequencies and dynamic Young′s modulus is not obvious, but Cl- can accelerate the erosion process of concrete witch cause baring bar, pockmark and other terrible erosions.