The effect of different Ce content on the microstructure and mechanical properties of Cr30Mo2 superferrite stainless steel was studied. The results show that the inclusion types in Cr30Mo2 superferrite stainless steel are mainly Cr oxides and Al-Si composite oxides with irregular shapes, which are converted into Ce2O3 after Ce addition and spherical composite inclusions rich in Al and Si in the core and Al and Ce in the outer layer, with small size, round shape and significantly reduced inclusion content. Ce2O3 can be used as heterogeneous nucleation core, which can increase casting nucleation rate and reduce grain size. However, excessive Ce content results in abnormal increase of grain size. Trace Ce can significantly improve the plasticity of Cr30Mo2 stainless steel at room temperature. Adding 0.07%Ce can increase the elongation after fracture from 1.5% to about 20%.