In order to explore the effect of steel slag coarse aggregate on sulfate resistance of concrete, erosion tests of concrete in different concentrations (5%, 10%, 15%,mass fraction) of sodium sulfate (Na2SO4) solution were carried out under different substitution rates of steel slag coarse aggregate (0%, 30%, 60%, 90%). Based on the entropy weight method, the comprehensive durability evaluation index D of steel slag coarse aggregate concrete was established with three typical durability indexes of concrete mass, compressive strength and relative dynamic elastic modulus as parameters. The influence of substitution rate of steel slag coarse aggregate and the concentration of Na2SO4 solution on durability of concrete were reflected by D value, and the service life of steel slag coarse aggregate concrete under different erosion conditions was predicted by GM(1,1) model of grey theory. The results show that in the whole erosion process, the D value of steel slag coarse aggregate concrete with steel slag substitution rate less than 60% is higher than that of ordinary concrete, indicating that concrete prepared with steel slag instead of natural aggregate can improve the sulfate resistance of concrete. The prediction results of GM(1,1) model are basically consistent with the experimental results, and the service life of concrete with 60% steel slag coarse aggregate substitution rate is better than that of other groups.