Patients with cognitive dysfunction are often accompanied by neuropathy, in which brain-derived neurotrophic factor (BDNF) plays an important role in the growth and survival of neurons. Current researches focus on its effect of improving motor dysfunction, but there is increasing evidence that BDNF also plays an important regulatory role in cognitive function. Nevertheless, most of the existing researches are limited to observing the change of its expression level, and fail to deeply explore the mechanism behind this change. This review summarizes the research progress of BDNF subtypes and their functions, and analyzes the relationship between BDNF and cognitive dysfunction from the aspects of learning and memory ability, synaptic structural plasticity and neurotransmitters, in order to provide reference for the basic research and clinical intervention of cognitive dysfunction.