The effect of magnesium and calcium treatment on morphology, size and distribution of sulfide in non-quenched and tempered 38MnS6 steel was investigated based on quantitative metallography and electron spectroscopy analysis. The results suggest that typeⅡ sulfide was replaced by typeⅢ and typeⅠafter magnesium and calcium treatment, and the distribution of sulfide became more uniform though the size was bigger. The hot deforming of sulfide decreases with content of modification agent in sulfide, and increases with the size of sulfide. An improved dispersion of sulfide can be achieved by combined magnesium and calcium treatment.