With rapid development of sequencing technologies such as deep sequencing and whole genome high-density tiling array, we now know that most of the “junk” genomic sequences are transcribed as non-coding RNAs (ncRNAs). A large number of long ncRNA transcripts (> 200bp) have been identified, and these long ncRNAs (LncRNAs) are found to be crucial regulators for epigenetic modulation, transcription, and translation. In this review, we briefly summarize the regulatory function of LncRNAs with a particular focus on the underlying mechanisms of LncRNAs in oncogenesis, tumor metastasis and suppression.