Abstract: The transposable element (TE) is considered to be a kind of repetitive sequence.TE and its category of various organisms and the transposition mechanism—the recombination and integration,the relationship for TE and host and the evolutionary significance of TE have been described in this paper.There is a close relationship between TE and population dynamics,natural selection,and genetic drift.TE can make the host to get new function,meantime may get lost from the host even the extinct of population or species.TE has been reported as gene regulatory sequences,enhancer,silencer and promotor regions.It may change pseudogene into true gene.It can regulate and influence the mitotic chromosomal crossover process,gene recombination,chromosome breakage and heterochromatin distribution so as to affect the chromosome morphology and construction.TE possess not only vertical transfer but also the horizontal or lateral transfer.With the mechanisms of genome immnuity,mechanical geneome incompatability and genome resetting,TE may provide the base for post-mating isolation and even the pre-mating one to lead to the speciation and lineage evolution.