Abstract: Populus yunnanensis is an important timber production tree species, but it is not widely planted in Yunnan Province for severe pests, especially for wood -boring insect that has become one of the most serious obstacles to industry development of P.yunnanensis.Gene Sbt -Cry Ⅲ, which encodes a protein that can kill Cerambycidaes of Coleoptera, was synthesized and an expression vector containing the gene was constructed, which laid the foundation for transferring the wood -boring pest resistant gene into P.yunnanensis by transgenic technique to solve the problem mentioned above.