Abstract: A cellulose degrade bacterium from the rumen of the sheep was indentified as Bacillus subtilis by using analysis of morphology and the conserved sequence 16S rDNA. Two different xylanase genes were cloned from the bacterium chromosome DNA by original strain of Bacillus subtilis. The two xylanase genes were connected with vector pMG36e to construct xylanase gene expression vector, and then transformed into E. coli and Lactococcus lactis MGr1363. Both them could express xylanase, and their enzyme activities reached 28.29 U/mL and 7.11 U/mL respectively,which were higher 13.04 times and 3.28 times than that of original strain of Bacillus sub tilis （ 2.17 U/mL）.