It has been generally agreed that pyridine can be effectively mineralized in aerated TiO₂ slurries using near-UV irradiation. The knowledge on the kinetics of the system possesses both practical and theoretical values. The present study, on the base of Langmuir–Hinshewood mechanism, illustrates a pseudo first-order kinetic model of the degradation with the limiting rate constant of 3.004mgl⁻¹min⁻¹ and equilibrium adsorption constant 2.763×10⁻²lmg⁻¹, respectively. The degradation efficiency in alkali is a little higher than that in acid with a minimum at about pH=5, which is explained by the formation of acid-pyridine in acidic surrounding together with the amphoteric nature of the TiO₂ surface. The promotion of H₂O₂ on the photo-degradation lies in its supplying proper amount of OH radicals for the inducement stage before surface redox reactions.