MicroRNA (miRNA) are small, non-coding endogenous RNAs with 20~25 nucleotides (nt) in length, which widely exist in eukaryotes and possess the function of regulating gene expression. miRNAs participate in various physiological/pathophysiological processes such as cell growth and development, cell differentiation, cell proliferation, apoptosis, hormone secretion and tumor formation. No matter in terms of the quantity or function of miRNAs, the current findings on miRNAs are not enough. So further study on miRNAs can help us to understand the mechanism of physiological and pathological in various organisms and provide new ideas and basis theoretical for disease diagnosis, judgment, prognosis and treatment ultimately. In recent years, along with the development of genomics and proteomics technology, miRNA microarray and mass spectrometric detection make miRNAs become a crucial role in the study of human diseases.