Long non-coding RNA was dismissed as merely transcriptional "noise" in the past decades. Numerous researches have shown that lncRNAs regulated gene expression at the epigenetic level. Moreover, lncRNAs played important roles in proliferation, apoptosis and invasiveness of tumor cells, and participated in metastatic capacity of cancers. Recent studies revealed HOX transcript antisense RNA, a lncRNA with regulatory functions of transcription, could bind PRC2 and LSD1/CoREST/REST complexes and direct to the specific gene sites, resulted in H3K27 methylation and H3K4 demethylation and ultimately gene silencing. Aberrant HOTAIR expression was associated with various sites of cancers such as breast, hepatocellular, gastric, colorectal, pancreatic et al; and affected survival and prognosis of cancer patients. In this review, we introduce an overall view of HOTAIR by describing the known molecular mechanisms and potential functions of HOTAIR and summarizing the latest progresses on the research of HOTAIR in various human cancers.