A desiccant cooling system includes a desiccant cooler including a desiccant cooling path through which air introduced from the outside passes, a desiccant dehumidifier on the desiccant cooling path to pass through air and remove humidity of the air, and a water cooling portion cooling cooling water by using the low-humidity air that has passed through the desiccant dehumidifier; and a vapor compression cooling device including a water cooled condenser disposed to be cooled by the cooling water cooled by the water cooling portion so as to condense a refrigerant flowing inside the water cooled condenser, wherein the refrigerant is circulated in the water cooled condenser.