Taking the relative dynamic elastic modulus as the evaluation index of freeze thaw damage, the damage degree of artificial sand concrete specimens under two freeze thaw cycles of water and NaCl solution with mass fraction of 3.5% was compared and analyzed, and the correlation was theoretically explained based on the osmotic pressure theory. The results show that there is a linear correlation between the cycles of water freeze thaw resistance and salt freeze thaw resistance, and the linear correlation has nothing to do with concrete mix proportion, strength grade and stone powder content. Further combined with the analysis of the data of the water sand freeze thaw resistance and salt freeze thaw resistance of natural sand concrete, the universality of this quantitative relationship is verified, that is, the water freeze thaw resistance of concrete is about 2.8 times its salt freeze thaw resistance.