In this paper naphtha feed characterization and reactor modeling are thoroughly investigated. Naphtha feed characterization method is based on the work of proposing candidate components which have the potential to provide behavior similar to the behavior of the original naphtha feed. HYSYS software is used to provide the thermodynamic properties for the different true boiling points distillation cuts of the naphtha feed. Physical and thermodynamic properties of the selected components which represent each volume fraction (cut) are related to the properties obtained from HYSYS. The results which are the predicted molar composition of the lumped chemical species of the feed are compared to the paraffin-naphthene-aromatic (P,N and A) analysis of the studied commercial data. The relative errors of the feed stream are around 5%. The kinetic model and reaction network are based on the major reforming reaction such as dehydrgenation of naphthenes, dehydrocyclization of paraffin, cracking of paraffins and hydrocracking of cycloalkanes. The characterized data and model were bench marked against the real production data of a Libyan local refinery and the final results of the reformer such as outlet temperatures and reformate octane number have shown deviations with the actual operating data which considered in direct relation with weak points inherited to characterization method.