The chloride permeability of concrete with slag or (20wt%, 30wt%, and 40wt% of binder) and binary slag and fly ash (the ratio of slag and fly ash 5:5, 4:6 and 6:4) was investigated in this study. The results show that the chloride permeability of concrete decreases firstly and increases latterly with the increasing of fly ash content. However, the permeability of concrete with slag decreases sharply with the slag content increases. Especially the content of slag is 40 wt%, the permeability is only 15.4% of the control concrete. The permeability of concrete using binary admixture of slag and fly ash is less than that of fly ash concrete and more than that of slag concrete.