In this paper, a simple model, but with high accuracy for a packed column liquid desiccant regenerator, to describe the heat and mass transfer process is developed. By lumping fluids' thermodynamic properties and the geometric specifications as constants, two equations related with seven identified parameters are developed to predict the heat and mass transfer rate for solution regeneration processes in the regenerator. Commissioning information and the Levenberg-Marquardt method are employed to determine the unknown parameters. Compared with previous models, the presented model is simply constructed and accurate and requires no iterative computations while applied in predicting the heat and mass transfer rate once the parameters of the proposed model are determined. Experimental results demonstrate that the current model is effective to predict the performance of desiccant regeneration in the,regenerator over wide working conditions. The proposed. model promises to have wide application for real-time performance monitoring, optimization, and control for liquid desiccant regeneration.