With the increasing prevalence of Alzheimer′s disease (AD), its pathogenesis has become an urgent problem in the medical community. microRNA involves in epigenetic regulation of protein synthesis and is a biological marker associated with a number of states, including AD. This paper mainly introduces progress made in the research of miRNA in AD in the respects of the newly discovered expression changes and regulatory pathways in vivo and in vitro and exosomes found recently to be able to preserve morphology of the miRNA secretion in the nervous system. The exosomes not only improve the detection rate of miRNA but also contribute to the damage in AD through inflammatory mediators.