Long noncoding RNAs (lncRNAs) are noncoding RNAs longer than 200 nucleotides,they can regulate gene expression at transcription and post-transcription level as signals,decoys,guides,and scaffolds.Compared to the expression of protein-coding genes,expression of lncRNAs is lower,but they have important function in X chromosome silencing,genomic imprinting,chromosome modification,transcription activation,transcription interference and nuclear transport.In comparison to small noncoding RNAs,the function of lncRNAs is largely unclear.Advance are highlighted according to origin,classification,molecular mechanism,function and evolution of long noncoding RNAs,which providing a guide for further study of function and molecular mechanism of lncRNAs.