Abstract: The effects of Ce on the inclusions and the impact toughness of 2Cr13 stainless steel were studied by metallographic examination, scanning electron microscope (SEM) and energy spectrum analysis. The results show that adding Ce into the steel improves the shape and size of inclusions. The fracture mode of 2Cr13 stainless steel is typical cleavage fracture, but quasi-cleavage and dimple fracture after adding Ce into the steel, and the spherical inclusions of rare earth oxysulfide in the dimple are the main factor for this transformation. The transverse impact toughness of 2Cr13 stainless steel is improved obviously by rare earth. In comparison with 2Cr13 stainless steel without Ce, the transverse impact toughness of 2Cr13 stainless steel with Ce is increased 54.55% at -40℃.