Combined corrosion-erosion (C-E) behavior of some commercial steelscontaining 2.25--25 wt-%Cr have been investigated at 850℃ using air as carryinggas and 130μm dia. SiC or Al_2O_3 as erodents. It was found that C-E behaviorstrongly depends on the corrosion resistance of steels. The C-E resistance increaseswith increasing Cr content, and a drastic raise of the resistance occurs at about9 wt-%Cr. Obvious influences of the nature and shape of the particles on the C-Erate of steels was noticed. Mechanisms of material degradation have also beendiscussed.