Abstract: Carbon steel strips with different phosphorus and carbon contents were produced by using the twin roll strip casting process. Fine grains and dendrite structure were observed in high-P steels. Negative phosphorus segregation was found in strip cast high-P and high-C steels. For the steels with different carbon contents, phosphorus distribution in the thickness direction of the strip is obviously different. This is because solutes are redistributed in the melting pool and the phosphorus segregation rate is associated with the length of the mushy zone and the phosphorus solubility in different phases. Phosphorus as a solute in ferrite can lead to the higher hardness and strength with lower plastic propertyies.