Cognitive impairment represents a mental health condition primarily affecting cognitive faculties such as learning, memory, perception, and problem-solving abilities. This condition frequently manifests in patients diagnosed with Alzheimer’s disease, vascular dementia, and mild cognitive impairment. In comparison to pharmaceutical interventions, acupuncture treatment offers distinct advantages, including cost-effectiveness, tolerability, and a strong safety profile, positioning it as a promising approach to enhance cognitive function. Numerous studies have demonstrated the significant impact of acupuncture in ameliorating cognitive deficits among individuals with cognitive impairment. However, the precise mechanisms underlying the cognitive enhancement achieved through acupuncture remain elusive. Building upon the theoretical principles of Chinese medicine, which emphasize the interconnectedness of the brain and the gastrointestinal system, and drawing from contemporary experimental investigations highlighting the intricate relationship between the brain-gut axis and acupuncture’s cognitive benefits, this paper undertakes a comprehensive examination of the mechanisms by which acupuncture may improve cognitive impairment. By elucidating these mechanisms through the lens of the brain-gut axis theory, this review aims to provide a foundational framework for further exploration of innovative acupuncture approaches for the treatment of cognitive impairment. Moreover, the study of the micro-level mechanisms involving gut microbes is propelled by our understanding of the brain-gut axis in cognitive enhancement through acupuncture. Nonetheless, gut microbial communities exhibit distinct characteristics, including individual variations, dynamic fluctuations, and a diverse range of species. Thus, it becomes imperative to investigate, enhance, and standardize novel acupuncture methods that specifically target the regulation of gut homeostasis. In this context, our review encompasses acupuncture and moxibustion interventions designed to address cognitive impairments through the prism of the brain-gut axis. These interventions encompass the preservation of gut microbial ecological equilibrium, the maintenance of gut microbiota diversity, the modulation of beneficial microbial population levels, the regulation of metabolic processes, the promotion of brain-derived neurotrophic factor (BDNF) production, the inhibition of microglial cell activation, the mitigation of neuroinflammatory responses, and the reduction of Aβ protein accumulation.