A desiccant cooling system includes a desiccant cooling device partitioned into a desiccant cooling path and a regeneration path and including a desiccant rotor having one side on the desiccant cooling path and other side on the regeneration path and a cooler configured to cool high-temperature low-humidity air which has been dehumidified while passing through the one side of the desiccant rotor; and a vapor compression cooling device including a compressor configured to compress a refrigerant, a condenser configured to be cooled by the air cooled by passing through the cooler, and condenses the refrigerant compressed by the compressor, an expansion valve configured to expand the refrigerant condensed by the condenser, and an evaporator configured to evaporate the refrigerant expanded by the expansion valve and transfer the evaporated refrigerant to the compressor.