The activation energies (E) for the reactions of quinoline-methyl, ethyl and n-propyl iodides in nitrobenzene and n-propyl alcohol have been determined.Their values are 14.4, 16.1&17.9 kcal/mole in nitrobenzene and 19.9, 25.4&24.9 kcal/mole in n-propyl alcohol respectively.As the iodides change, the change of E are different in the two solvents.Experimental results give no simple correlation between activation energies, frequency factors and the molecular structure.But a linear relationship was found between the logarithms of the rate constant and the inductive effect index of the alkyl group of the iodides.