Abstract: MicroRNAs(miRNAs) are a large group of noncoding small RNA molecules with 20-25 nucleotides that have capability of regulating gene expression at posttranscriptional levels by antisense complementarily to specific target messenger mRNAs.miRNAs regulate almost every signaling pathway and play crucial roles in diverse biological processes, such as cell development, differentiation, apoptosis, and proliferation.It has been shown that aberrant expression of miR-181a is involved in the development and progression of many types of cancer through regulating functional proteins and the network of signaling pathways related to cell proliferation, migration and invasion, programmed cell death, and cell survival and modulate cancer development, progression, and metastasis.Here we discuss the recent findings of miR-181a researches regarding gene structure, gene expression and regulation, biological function, and its correlation with pathogenesis and progression of human malignant tumors.