Four groups of replacement ratios of recycled coarse aggregate (0%,20%, 50% and 100%) were designed in order to study the effect of different replacement ratios of recycled coarse aggregate (RCA) on the corrosion resistance of recycled concrete under dry and wet cycle conditions. And the mass loss rate, relative dynamic modulus and residual compressive strength of recycled coarse aggregate were measured respectively. At the same time, the microstructure changes and products of recycled concrete after sulfate attack were analyzed by SEM and EDS. The results show that the content of recycled aggregate is an important factor affecting the mass loss rate, relative dynamic modulus and residual compressive strength of recycled concrete. With the increase of recycled coarse aggregate, the mass loss rate of recycled concrete after sulfate attack increases, and the residual relative dynamic modulus decreases, and the compressive strength decreases. The addition of recycled coarse aggregate will weaken the anti-sulfate corrosion performance of concrete and the greater the amount of recycled coarse aggregate is added, the more obvious the effect will be.