Abstract: The pore structure of coal gasification fine slag in Ningxia was characterized and analyzed by low temperature nitrogen adsorption, scanning electron microscope and low field NMR. The pore morphology is mainly fracture shape, and the BET specific surface area of each particle size is large, which is 125.78−589.78 m²/g. The SEM analysis shows that the BJH pore diameter is quite different from the actual situation, and the analysis of pore structure only by low-temperature nitrogen adsorption method has certain limitations. The low field NMR method shows that the products pore sizes of all particle sizes contain micropores, transition pores, mesopores and macropores, and the total porosity is about 27%, mainly mesopores and macropores, followed by micropores and transition pores. The pore structure shows that the products of different particle sizes of coal gasification fine slag have certain adsorption properties, but the medium and large pores are the main storage space of water, resulting in difficulty in dehydration.