In order to apply as a desiccant for desiccant cooling system, zeolites were modified. Dealumination and Ion exchange of zeolites increased the silica to alumina ratio by EDTA treatment and converted sodium cation into alkai metal cations such as lithium, magnesium, calcium, and potassium. As a result of comparison of adsorption isotherm, EDTA 0.5~0.6 g/g zeolite treated and lithium ion exchanged zeolites exhibited ideal isotherm. (R=0.1)