In this paper pure carbon, pure iron and single crystall silicon were firstly loaded into a pure graphite crucible to obtain a hypereutectic Fe-C melt by carburizing at high temperatures. The powder Ce2S3 was added to the melt with different proportion under the same process conditions and cast iron samples were obtained. The graphite morphology of the samples was observed under optical microscope. Then matrix of the samples was etched by electrolysis way. At last the non-ferrous residue gathered from the surface of cast iron sample after electrolysis process was calcined and analysed with BEI and EDS to find the trace of Ce2S3. The results showed that the powder Ce2S3 was really added into the melt but did not make any change in graphite morphology.The only effect of Ce2S3 was to make the amount of graphite increase slightly.All results of this paper indicat that the additive Ce2S3 is only the base for graphite flake to precipitate but is not a sufficient condition for graphite to nodularize.