The corrosion resistance of four kinds magnesite-chrome bricks against converter salg was investigated by static crucible slag tests. The microstructures of the as-delivered and tested refractories were analyzed by means of SEM and EDS. The results showed that: Different magnesite-chrome bricks have different slag resistances. Generally, the slag resiantance sequence is as follows: rebounded fused magnesite-chrome brick＞semi-rebounded magnesite-chrome brick＞direct-bonded magnesite-chrome brick＞silicate bonded magnesite-chrome brick. Slag reacts with the periclase of magnesite-chrome refractories, which results in the dissoving of periclase in fayalite slag. However, the complex spinels have superior slag resistance.