Dehumidifier is the core component in a liquid desiccant air-conditioning system, whose efficiency directly affects the whole performance. In this study a cross-flow dehumidifier was established in which LiCl solution and Celdek structured packing were used. Enthalpy efficiency and moisture efficiency were adopted to describe the heat and mass transfer performance of the dehumidifier. Influence of desiccant and air inlet parameters on the dehumidifier performance was experimentally investigated, and efficiency comparison in different air outlet regions was also carried out, as well as influence of packing structure size on dehumidifier performance. The results show that the outlet parameter values of air and solution can be easily gained with enthalpy efficiency and moisture efficiency which was obtained from experimental regression. Efficiency has obvious regional characteristics. By increasing the thickness, width or height simultaneously, better performance of Dehumidifier can be achieved without increasing the pressure loss. (C) 2011 Elsevier Ltd. All rights reserved.