Using homolog blasting strategy or RECE technique,five precursor miRNAs of larch were obtained.The result demonstrated that mature miRNAs shared high similarity among plant species,while the non-mature sequences showed distinct similarity,which related to genetic relationship.Expression profiles of five precursor and mature miRNAs during eight developmental stages were studied,using qRT-PCR technique.The result demonstrated that the expression of precursor and mature miRNAs changed dynamically during different developmental stages.The major peaks of mature miRNAs were reached at late cytoledonary embryo,which might be associated with promoting embryo dormancy.However,the minor peaks were distinct,such as,miR397 and miR408 was at PEMIII,miR398 at early single embryo,miR156 and miR166 at early cytoledonary embryo,which might be related to regulation for keeping thin cell wall,proton transferring between photo systems,formation of shoot meristem.However,the expression of mature miRNAs did not be correlated to precursor miRNAs linearly,which might be regulated at several levels.Our study sheds light on the MIR revolution,expression regulation of mature miRNA,and regulatory function on somatic embryogenesis of larch.