The invention relates to the coal processing field and discloses a cooling system and method for direct coal liquefaction residue. The system comprises a first cooling unit and a second cooling unit.The first cooling unit is used for performing first cooling operation on pressure-reducing residual slag from a pressure-reducing tower bottom using direct coal liquefaction. The first cooling operation is performed in such a manner of guiding pressure-reducing residual slag into a mechanical piston jacket-type cooler and indirectly contacting the pressure-reducing residual slag with cooling mediums a ling medium. The second cooling unit is used for performing second cooling operation on pressure-reducing residual slag subjected to first cooling operation. The second cooling operation is performed in such a manner of guiding pressure-reducing residual slag subjected to first cooling operation into a gas cooler and directly or indirectly contacting the pressure-reducing residual slag with the cooling mediums. With the above-mentioned cooling system and method for direct coal liquefaction residue, a large quantity of cooling water and other utilities are no longer consumed. Therefore, the effect of evidently saving energy and saving water is obtained. Additionally, the method helps avoid generation of industrial waste water.