Coal gasification technology has developed rapidly as a clean utilization technology, but a large amount of coal gasification slag has been produced at the same time. With the sources and hazards, the basic properties, the prepared materials (mesoporous materials, activated carbon, composite materials) and the application of coal gasification slag (in the field of waste gas and wastewater treatment, construction and building materials, agriculture) involved, this article reviews the research status, analyzes the existing problems and forecasts application prospects. Coal gasification slag is rich in carbon, aluminum and silicon, with large specific surface area and relatively developed pore structure. Then it can be used to prepare high-value products. However, the waste liquid generated during the preparation process needs to be urgently treated and disposed of. The remaining aluminum, silicon and carbon-containing residues also need to be recycled. Although the research on coal gasification slag has achieved good results, most are still in the stage of laboratory research or experimental promotion, and cannot achieve large-scale utilization. In this paper, it is suggested that developing resource utilization technology of coal gasification slag with simple process, strong feasibility and economic benefits, the synergistic utilization of aluminum, silicon and carbon resources should be realized on the basis of hierarchical utilization, and large-scale utilization should be achieved on the ground of full utilization.