Abstract: By nomograph, the average boiling point and the relationship between density and temperature of the feedstock can be established using a correlation formula developed when the complete distillation data of feedstock are available. The characterization factor is then able to be calculated based on the correlations of the average boiling points and density of feedstock. Using feedstock density and temperature at distillation volume of 10%, another correlation for calculating the average boiling points is also developed. This correlation can be used to evaluate the characterization factor with routine analysis data of FCC feed. The relative error of the correlation is less than 4%. Therefore, the correlation has good simulation accuracy.