The reaction rates of 4-ethyl pyridine with p-methyl benzylbromide have been measured by conductometry in acetonitrile, and the rate constants of these reactions are determined in accordance with various temperatures (20, 25, 30$^{circ}C$) and pressures (1, 200, 500, 1000 bar). The rate constants increased with the higher pressure and temperature. The activation energies and activation parameter values of these reactions are calculated by determination of the rate constants the same. The activation volume, activation compressibility coefficient and the activation entropy are all negative. The result of kinetic studies for the pressure show that this reaction proceeds in typical bimolecular nucleophilic substitution reaction.