To this end, an efficient and automatic reactive site-based conformer search method for transition states is developed in this work. It is used to develop a universal reaction kinetic mechanism model based on the transition state theory and the DFT method for accurate predictions of CO2 chemical absorption rate constants in various amine-solvent solutions involving primary, secondary, tertiary amines and water, methanol, ethanol solvents. By utilizing the transition state conformer search method, the prediction accuracy of the reaction kinetic model is significantly enhanced. This paper is organized as follows. In the second section, the developments of the reaction kinetic model and the conformer search method for transition states are introduced. In the third section, the prediction results of the reaction kinetic model with/without the conformer search method are presented and discussed. Also, the influence mechanism of the transition state conformers on reaction kinetics of amine-based CO2 chemical absorptions are studied by the analysis methods of weak interactions and reactive site charges.