A new composite desiccant composed of ceramic fiber, silica gel and lithium chloride was developed. The adsorption mechanism of the new composite desiccant was analysis based on the adsorption isotherm and the micro character. Compared with the silica gel the chemical absorption accounted for a leading role for composite desiccant. Furthermore the dynamic dehumidification property of the wheel fabricated by composite desiccant was tested. The result showed the composite desiccant wheel need longer time to reach stable dehumidification amounts.