通过显微组织观察、成分分析和热力学计算，研究了变质处理对超高锰钢铸态和热处理组织的影响。结果表明，变质处理可使铸态组织中的奥氏体晶粒明显细化，晶界碳化物的网状特征消失；使热处理组织中的夹杂物球化，碳化物细化，且分布更加均匀弥散；超高锰钢凝固时的形核次序为ＣａＳ（ＣｅＳ）→ＴｉＣ→Ｆｅ３Ｃ（奥氏体），它们可通过两次匹配异质形核的方式提高形核率，增强变质效果。 Through microstructure observation, composition analysis and thermodynamic calculation, the effect of modification treatment on as-cast and heat-treated microstructure of ultra-high manganese steel was studied. The results show that the metamorphic treatment can refine the austenite grains in the as-cast microstructure and eliminate the reticular features of the grain boundary carbides. The inclusions in the heat-treated structure are nodular and the carbides are refined and the distribution is more uniform The order of nucleation during the solidification of ultra-high manganese steel is CaS (CeS) → TiC → Fe3C (austenite). They can improve the nucleation rate and enhance the metamorphic effect by matching the heterogeneous nuclei twice.