The microRNA is only 20-22 nucleotides in length and can work as post-DNA transcription regulator for gene expression. It has an important regulating role in the life process such as cell aging, disease and so on. So microRNA has a huge potential for anti-aging and disease treatment. Nowadays it has become one of the most intense interests to the tissue engineering and other area of medicine. In this paper, the biogenesis, mechanism, relationship with cell aging and age-associated diseases and the clinical application of microRNA were reviewed.