Abstract: The present invention relates to a composition for preventing or treating a neuroinflammatory disease, which can inhibit the expression of neuroinflammatory cytokines, promote the degradation of amyloid beta, and improve a cognitive function in an animal model of Alzheimer's disease. More specifically, the present invention relates to a composition for preventing or treating a neuroinflammatory disease comprising didanosine or a pharmaceutically acceptable salt thereof, and the composition may be used for the development of drugs and quasi-drug materials.