Pulse radiolysis of aqueous quinoline in dilute solutions under different conditions was studied. The main characteristic peaks in the transient absorption spectra were attributed and the build−up/decay trends of several transient species were investigated. Under alkaline conditions, interactions between OH radicals and quinoline molecules yield OH−adducts with a rate constant of 5.5×10,9, L/mol,−1, s,−1,. Under acidic conditions, quinoline molecules react with H,+, radicals to form quinoline cations, which react with OH radicals to yield quinoline cation OH−adducts with a rate constant of 7.90×10,9, L/mol,−1, s,−1,. The reaction mechanism of OH in alkaline conditions and in neutral conditions are the same, the rate constant in neutral condition is 7.15×10,9, L/mol,−1, s,−1,. The reaction of H with quinoline produces H–adduct. In neutral solutions, e,aq,−, react with quinoline and produce quinoline anion with a rate constant of 7.05×10,9, L/mol,−1, s,−1,.