Abstract: The Claus process is widely applied in sulphur-containing gas processing, but the tail gas from traditional Claus reactors cannot meet current emission requirements due to the thermodynamic reaction equilibrium of the Claus reaction. The novel hydrogenation and absorption process converts SO₂, organic sulphides and elemental sulphides in Claus tail gas into H₂S, and H₂S is concentrated and returns back to Claus reactors. Thus, the process can acquire high sulphur conversion. However, literatures related to kinetic studies of Claus tail gas hydrogenation are rather limited. An appropriate reaction kinetic model for the tail gas hydrogenation not only contributes to the scale-up of the hydrogenation reactor, but also benefits the process optimization of Claus desulphurization. A power exponent type reaction kinetic model for the hydrogenation reaction of tail gas was proposed in this work and the parameters in kinetic model were estimated using improved genetic algorithm. An approximate value near the global minimum can be obtained by the genetic algorithm, but it requires rather long time and considerable computing resources to obtain the exact numerical solution due to the intrinsic properties of the traditional algorithm. The genetic algorithm can be improved by combining with the Marquardt algorithm in which the calculation stops if a calculation fault occurs in the searching process and steps into the next set of calculations instead. The improved algorithm can obtain the optimal solution at the global range and becomes more stable and more flexible compared to the traditional genetic algorithm. The statistic test and error analysis have demonstrated that the calculation results are in consistence to the experimental data, supporting the effectiveness of the established model.