Abstract: An air-liquid composite cooler for a memory module is provided. The memory module has a top portion and two side portions. The air-liquid composite cooler includes a liquid-cooling structure and a pair of air-cooling structures. The liquid-cooling structure is arranged on the top portion and has a liquid passage. The air-cooling structure is arranged on a side portion, and includes a phase-change thermo-conductive member. One end of the phase-change thermo-conductive member contacts the liquid-cooling structure to conduct heat and another end of the phase-change thermo-conductive member is extended in a direction away from the liquid-cooling structure. Therefore, the overall cooling efficiency of the cooler may be improved.