Many investigations have demonstrated that microRNA (miRNA) is not only involved in the modulation of nerve cell growth and physiological activity, but also responsible for dysfunctions in synaptogenesis or synaptic plasticity, neurodegenerative diseases, tumorgenesis in the nervous system, as well as in cerebrovascular disorders. With the intensive researches in miRNA, it is possible gradually to explain the related pathogenic mechanisms of some major diseases in the nervous system.