Comparison of the calculated σ～△～E^H^O or σ～△～E^L^U values with the electrophilic or nucleophilic reactivities at benzene ring of more than sixty Ph(X)n molecules taken from the experimental data found in literature has been carried out. The σ～△～E^H^O value accupately be positively parallel to the intramolecular and intermolecular electrophilic reactivity and vice versa for the σE^L^U value, while the cases of CN, CF3 and F groups are exceptional.

Key words: REACTIVITY, BENZENE P, ELECTROPHILIC REACTION, SUBSTITUENT EFFECT, ELECTRONIC EFFECT, NUCLEOPHILIC REACTION