Abstract: In order to investigate the degradation law of chloride salt corrosion resistance of recycled coarse aggregate concrete after replacing crushed stone with different mass ratios (0, 50%, 100%) and slag powder with 25% mass ratio instead of cement, this study conducted relevant experiments. A 10% NaCl solution was used to conduct 0, 150, and 300 wet dry cycle corrosion tests and chloride penetration tests on recycled coarse aggregate concrete with different ratios. By testing the compressive strength, mass loss rate, and chloride penetration resistance of concrete, analyze its variation patterns. The experimental results show that the compressive strength and resistance to chloride ion penetration of recycled coarse aggregate concrete decrease with the increase of recycled coarse aggregate mass ratio, and the mass loss rate increases with the increase of recycled coarse bone mass ratio; Adding 25% by mass of slag powder can improve the compressive strength of recycled coarse aggregate concrete after 300 cycles of dry wet corrosion, reduce mass loss rate, and enhance its resistance to chloride penetration; When the mass ratio of slag powder is 25% and the mass ratio of recycled coarse aggregate is 50%, the recycled coarse aggregate concrete has the best resistance to chloride corrosion; Moderate addition of slag powder can enhance the chloride salt corrosion resistance of recycled coarse aggregate concrete.